Compile all fiddle examples locally

Motivation: it would be a good idea if the API documentation examples
were checked into the skia repository, so we could make sure they
compile as part of the commit queue.

Fiddle would make/update a named fiddle each time it gets a new
commit of Skia, extracted from the code in the examples/ directory.
The docs would point at those named fiddles.  Named fiddles have urls
in the form:

    https://fiddle.skia.org/c/@Bitmap_000

Then we would stick a link to the example into the header documentation
like this:

    /** Allocates the pixel memory for the bitmap, given its dimensions
        and SkColorType. Returns true on success, where success means
        either setPixels() or setPixelRef() was called.

        @param bitmap  SkBitmap containing SkImageInfo as input, and
                       SkPixelRef as output
        @return        true if SkPixelRef was allocated

        @example       https://fiddle.skia.org/c/@Bitmap_000
    */
    bool allocPixelRef(SkBitmap* bitmap) override;

There are still around 200 disabled examples that need to be fixed
(these result from API changes since the author left).

Change-Id: I14a31348a9ccaaa31f65424b91e3a3533d2583a7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/198824
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
diff --git a/docs/examples/ImageInfo_019.cpp b/docs/examples/ImageInfo_019.cpp
new file mode 100644
index 0000000..fe4e74e
--- /dev/null
+++ b/docs/examples/ImageInfo_019.cpp
@@ -0,0 +1,29 @@
+// Copyright 2019 Google LLC.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+#include "fiddle/examples.h"
+// HASH=de418ccb42471d1589508ef3955f8c53
+REG_FIDDLE(ImageInfo_019, 256, 128, false, 0) {
+void draw(SkCanvas* canvas) {
+    const int width = 256;
+    const int height = 32;
+    SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
+    SkColor  gradColors[] = { 0xFFAA0055, 0xFF11CC88 };
+    SkPoint  gradPoints[] = { { 0, 0 }, { width, 0 } };
+    SkPaint gradPaint;
+    gradPaint.setShader(SkGradientShader::MakeLinear(gradPoints, gradColors, nullptr,
+                    SK_ARRAY_COUNT(gradColors), SkShader::kClamp_TileMode));
+    SkBitmap bitmap;
+    bitmap.allocPixels(SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
+    SkCanvas offScreen(bitmap);
+    offScreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
+    canvas->drawBitmap(bitmap, 0, 0);
+    bitmap.allocPixels(SkImageInfo::MakeS32(width, height, kPremul_SkAlphaType));
+    SkCanvas sRGBOffscreen(bitmap);
+    sRGBOffscreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
+    canvas->drawBitmap(bitmap, 0, 48);
+    SkBitmap noColorSpaceBitmap;
+    noColorSpaceBitmap.setInfo(SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
+    noColorSpaceBitmap.setPixels(bitmap.getAddr(0, 0));
+    canvas->drawBitmap(noColorSpaceBitmap, 0, 96);
+}
+}  // END FIDDLE