Fix end-of-pattern matching for Skia recording optimization.

tests/PictureTest.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBlurImageFilter.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
@@ skipping 1592 matching lines @@
     SkAutoTUnref<SkPicture> picture(recorder.endRecording());
 }
 
 DEF_TEST(Canvas_EmptyBitmap, r) {
     SkBitmap dst;
     dst.allocN32Pixels(10, 10);
     SkCanvas canvas(dst);
 
     test_draw_bitmaps(&canvas);
 }
+
+DEF_TEST(DontOptimizeSaveLayerDrawDrawRestore, reporter) {
+    // This test is from crbug.com/344987.
+    // The commands are:
+    //   saveLayer with paint that modifies alpha
+    //     drawBitmapRectToRect
+    //     drawBitmapRectToRect
+    //   restore
+    // The bug was that this structure was modified so that:
+    //  - The saveLayer and restore were eliminated
+    //  - The alpha was only applied to the first drawBitmapRectToRect
+
+    // This test draws blue and red squares inside a 50% transparent
+    // layer.  Both colours should show up muted.
+    // When the bug is present, the red square (the second bitmap)
+    // shows upwith full opacity.
+
+    SkImageInfo onePixelII = SkImageInfo::Make(1,1,kBGRA_8888_SkColorType,kPremul_SkAlphaType);

[robertphillips, 2014/07/30 19:03:49]

blueBM? - Skia doesn't use '_' in variable names.

[dneto, 2014/07/30 19:26:20]

Done.

+    SkBitmap bm_blue;
+    make_bm(&bm_blue,100,100,SkColorSetARGB(255,0,0,255),true);

[robertphillips, 2014/07/30 19:03:49]

redBM?

[dneto, 2014/07/30 19:26:20]

Done.

+    SkBitmap bm_red;
+    make_bm(&bm_red,100,100,SkColorSetARGB(255,255,0,0),true);

[robertphillips, 2014/07/30 19:03:50]

semiTransparent?

[dneto, 2014/07/30 19:26:20]

Done.

+    SkPaint semi_transparent;
+    semi_transparent.setAlpha(0x80);
+
+    SkPictureRecorder recorder;
+    SkCanvas* canvas = recorder.beginRecording(100,100);
+    canvas->drawARGB(0,0,0,0);
+
+    canvas->saveLayer(0, &semi_transparent);
+    canvas->drawBitmap(bm_blue, 25, 25);
+    canvas->drawBitmap(bm_red, 50, 50);
+    canvas->restore();
+
+    SkPicture* picture = recorder.endRecording();

[mtklein, 2014/07/30 18:47:26]

As written this leaks.  Best to clean it up!

SkAutoTUnref<SkPicture> picture(recorder.endRecording());

(Don't worry about SkCanvas* canvas = ... above.  The recorder will track that
lifetime.)

[dneto, 2014/07/30 19:26:20]

Done.

+
+    // Now replay the picture back on another canvas
+    // and check a couple of its pixels.

[robertphillips, 2014/07/30 19:03:50]

replayBM?

[dneto, 2014/07/30 19:26:20]

Done.

+    SkBitmap bm_replay;
+    make_bm(&bm_replay,100,100,SK_ColorBLACK,false);
+    SkCanvas replayCanvas(bm_replay);
+    picture->draw(&replayCanvas);
+    replayCanvas.flush();
+
+    SkColor darkBlue = SkColorSetARGB(0xff,0,0,0x80);
+    SkColor darkRed = SkColorSetARGB(0xff,0x80,0,0);
+
+    uint32_t blueDot = 0xdeadbeef;
+    uint32_t redDot = 0xdeadbeef;
+
+    REPORTER_ASSERT(reporter, replayCanvas.readPixels(onePixelII,&blueDot,4,30,30));

[mtklein, 2014/07/30 18:47:26]

This is all fine, but I think you can replace everything after
replayCanvas.flush() with

REPORTER_ASSERT(reporter, bm_replay.getColor(30, 30) == 0xFF000080);
REPORTER_ASSERT(reporter, bm_replay.getColor(55, 55) == 0xFF800000);

[dneto, 2014/07/30 19:26:20]

Done.

+    REPORTER_ASSERT(reporter, replayCanvas.readPixels(onePixelII,&redDot,4,55,55));
+
+    REPORTER_ASSERT(reporter, blueDot == darkBlue );
+    // With the bug present, we would get a fully opaque red intead of
+    // a dark red.
+    REPORTER_ASSERT(reporter, redDot == darkRed );
+}