Fix computation of clipped src rect when tiling bitmaps in SkGpuDevice
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2252913004

Review-Url: https://codereview.chromium.org/2252913004
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 44d4354..864d124 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -686,8 +686,6 @@
     SkRect clippedSrcRect = SkRect::Make(*clippedSrcIRect);
     inv.mapRect(&clippedSrcRect);
     if (srcRectPtr) {
-        // we've setup src space 0,0 to map to the top left of the src rect.
-        clippedSrcRect.offset(srcRectPtr->fLeft, srcRectPtr->fTop);
         if (!clippedSrcRect.intersect(*srcRectPtr)) {
             clippedSrcIRect->setEmpty();
             return;