Remove deferred clear from SkGpuDevice

Add combining to GrClearBatch

Fix issue with state tracking in GrGLGpu::createTestingOnlyBackendTexture

Add tests for clearing GPU SkSurfaces and add tests for GrDrawContext::clear().

Add comment that SkCanvas::flush will resolve the RT in the GPU case.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1658823002

Review URL: https://codereview.chromium.org/1658823002
diff --git a/tests/ClearTest.cpp b/tests/ClearTest.cpp
new file mode 100644
index 0000000..a36c439
--- /dev/null
+++ b/tests/ClearTest.cpp
@@ -0,0 +1,236 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+#include "GrDrawContext.h"
+#include "GrGpu.h"
+#include "GrRenderTarget.h"
+#include "GrTexture.h"
+#include "GrTextureProvider.h"
+
+static bool check_rect(GrDrawContext* dc, const SkIRect& rect, uint32_t expectedValue,
+                       uint32_t* actualValue, int* failX, int* failY) {
+    GrRenderTarget* rt = dc->accessRenderTarget();
+    int w = rect.width();
+    int h = rect.height();
+    SkAutoTDeleteArray<uint32_t> pixels(new uint32_t[w * h]);
+    memset(pixels.get(), ~expectedValue, sizeof(uint32_t) * w * h);
+    rt->readPixels(rect.fLeft, rect.fTop, w, h, kRGBA_8888_GrPixelConfig, pixels.get());
+    for (int y = 0; y < h; ++y) {
+        for (int x = 0; x < w; ++x) {
+            uint32_t pixel = pixels.get()[y * w + x];
+            if (pixel != expectedValue) {
+                *actualValue = pixel;
+                *failX = x + rect.fLeft;
+                *failY = y + rect.fTop;
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+// We only really need the DC, but currently the DC doesn't own the RT so we also ref it, but that
+// could be dropped when DC is a proper owner of its RT.
+static bool reset_dc(SkAutoTUnref<GrDrawContext>* dc, SkAutoTUnref<GrSurface>* rtKeepAlive,
+                     GrContext* context, int w, int h) {
+    SkDEBUGCODE(uint32_t oldID = 0;)
+    if (*dc) {
+        SkDEBUGCODE(oldID = (*dc)->accessRenderTarget()->getUniqueID();)
+        rtKeepAlive->reset(nullptr);
+        dc->reset(nullptr);
+    }
+    context->freeGpuResources();
+
+    GrTextureDesc desc;
+    desc.fWidth = w;
+    desc.fHeight = h;
+    desc.fConfig = kRGBA_8888_GrPixelConfig;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
+
+    rtKeepAlive->reset(context->textureProvider()->createTexture(desc, true));
+    if (!(*rtKeepAlive)) {
+        return false;
+    }
+    GrRenderTarget* rt = (*rtKeepAlive)->asRenderTarget();
+    SkASSERT(rt->getUniqueID() != oldID);
+    dc->reset(context->drawContext(rt));
+    return SkToBool(*dc);
+}
+
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ClearBatch, reporter, context) {
+    static const int kW = 10;
+    static const int kH = 10;
+
+    SkIRect fullRect = SkIRect::MakeWH(kW, kH);
+    SkAutoTUnref<GrDrawContext> drawContext;
+    SkAutoTUnref<GrSurface> rtKeepAlive;
+
+    // A rectangle that is inset by one on all sides and the 1-pixel wide rectangles that surround
+    // it.
+    SkIRect mid1Rect = SkIRect::MakeXYWH(1, 1, kW-2, kH-2);
+    SkIRect outerLeftEdge = SkIRect::MakeXYWH(0, 0, 1, kH);
+    SkIRect outerTopEdge = SkIRect::MakeXYWH(0, 0, kW, 1);
+    SkIRect outerRightEdge = SkIRect::MakeXYWH(kW-1, 0, 1, kH);
+    SkIRect outerBottomEdge = SkIRect::MakeXYWH(0, kH-1, kW, 1);
+
+    // A rectangle that is inset by two on all sides and the 1-pixel wide rectangles that surround
+    // it.
+    SkIRect mid2Rect = SkIRect::MakeXYWH(2, 2, kW-4, kH-4);
+    SkIRect innerLeftEdge = SkIRect::MakeXYWH(1, 1, 1, kH-2);
+    SkIRect innerTopEdge = SkIRect::MakeXYWH(1, 1, kW-2, 1);
+    SkIRect innerRightEdge = SkIRect::MakeXYWH(kW-2, 1, 1, kH-2);
+    SkIRect innerBottomEdge = SkIRect::MakeXYWH(1, kH-2, kW-2, 1);
+
+    uint32_t actualValue;
+    int failX, failY;
+
+    static const GrColor kColor1 = 0xABCDEF01;
+    static const GrColor kColor2 = ~kColor1;
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Check a full clear
+    drawContext->clear(&fullRect, kColor1, false);
+    if (!check_rect(drawContext, fullRect, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Check two full clears, same color
+    drawContext->clear(&fullRect, kColor1, false);
+    drawContext->clear(&fullRect, kColor1, false);
+    if (!check_rect(drawContext, fullRect, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Check two full clears, different colors
+    drawContext->clear(&fullRect, kColor1, false);
+    drawContext->clear(&fullRect, kColor2, false);
+    if (!check_rect(drawContext, fullRect, kColor2, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor2, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Test a full clear followed by a same color inset clear
+    drawContext->clear(&fullRect, kColor1, false);
+    drawContext->clear(&mid1Rect, kColor1, false);
+    if (!check_rect(drawContext, fullRect, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Test a inset clear followed by same color full clear
+    drawContext->clear(&mid1Rect, kColor1, false);
+    drawContext->clear(&fullRect, kColor1, false);
+    if (!check_rect(drawContext, fullRect, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Test a full clear followed by a different color inset clear
+    drawContext->clear(&fullRect, kColor1, false);
+    drawContext->clear(&mid1Rect, kColor2, false);
+    if (!check_rect(drawContext, mid1Rect, kColor2, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor2, actualValue,
+               failX, failY);
+    }
+    if (!check_rect(drawContext, outerLeftEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerTopEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerRightEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerBottomEdge, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Test a inset clear followed by a different full clear
+    drawContext->clear(&mid1Rect, kColor2, false);
+    drawContext->clear(&fullRect, kColor1, false);
+    if (!check_rect(drawContext, fullRect, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Check three nested clears from largest to smallest where outermost and innermost are same
+    // color.
+    drawContext->clear(&fullRect, kColor1, false);
+    drawContext->clear(&mid1Rect, kColor2, false);
+    drawContext->clear(&mid2Rect, kColor1, false);
+    if (!check_rect(drawContext, mid2Rect, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+    if (!check_rect(drawContext, innerLeftEdge, kColor2, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, innerTopEdge, kColor2, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, innerRightEdge, kColor2, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, innerBottomEdge, kColor2, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor2, actualValue,
+               failX, failY);
+    }
+    if (!check_rect(drawContext, outerLeftEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerTopEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerRightEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerBottomEdge, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+
+    if (!reset_dc(&drawContext, &rtKeepAlive, context, kW, kH)) {
+        ERRORF(reporter, "Could not create draw context.");
+        return;
+    }
+    // Swap the order of the second two clears in the above test.
+    drawContext->clear(&fullRect, kColor1, false);
+    drawContext->clear(&mid2Rect, kColor1, false);
+    drawContext->clear(&mid1Rect, kColor2, false);
+    if (!check_rect(drawContext, mid1Rect, kColor2, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor2, actualValue,
+               failX, failY);
+    }
+    if (!check_rect(drawContext, outerLeftEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerTopEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerRightEdge, kColor1, &actualValue, &failX, &failY) ||
+        !check_rect(drawContext, outerBottomEdge, kColor1, &actualValue, &failX, &failY)) {
+        ERRORF(reporter, "Expected 0x%08x but got 0x%08x at (%d, %d).", kColor1, actualValue,
+               failX, failY);
+    }
+}
+#endif