Fixes use-of-uninitialized-value MSan error in image_skia_unittest

ui/gfx/image/image_skia_unittest.cc

Index: ui/gfx/image/image_skia_unittest.cc
diff --git a/ui/gfx/image/image_skia_unittest.cc b/ui/gfx/image/image_skia_unittest.cc
index 15337a863a9d34dfffbd05bf44e6999065057a0d..f4f63cf7a5a393ecd8e5b0e15b832ae12c5144e3 100644
--- a/ui/gfx/image/image_skia_unittest.cc
+++ b/ui/gfx/image/image_skia_unittest.cc
@@ -9,9 +9,11 @@
 #include "base/threading/simple_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
 #include "ui/gfx/image/image_skia_rep.h"
 #include "ui/gfx/image/image_skia_source.h"
-#include "ui/gfx/size.h"
 #include "ui/gfx/switches.h"
 
 // Duplicated from base/threading/non_thread_safe.h so that we can be
@@ -54,7 +56,11 @@ class DynamicSource : public ImageSkiaSource {
 
   virtual ImageSkiaRep GetImageForScale(float scale) OVERRIDE {
     last_requested_scale_ = scale;
-    return gfx::ImageSkiaRep(size_, scale);

[oshima, 2014/05/15 16:14:13]

this constructor is used in other tests (and only in tests) and they expects the
content is valid (because ImageSkiaRep::bitmap() is const), so probably better
to fix it in the constructor.

You can just call

bitmap_.eraseColor(<color>);

there

[Jun Mukai, 2014/05/16 01:57:33]

Done.

+    // The returned image can be resized in ImageSkiaStorage, so
+    // empty ImageSkiaRep could cause use-of-uninitialized-value.
+    gfx::Canvas canvas(size_, scale, true);
+    canvas.FillRect(Rect(size_), SK_ColorRED);
+    return canvas.ExtractImageRep();
   }
 
   float GetLastRequestedScaleAndReset() {
@@ -504,8 +510,9 @@ TEST_F(ImageSkiaTest, ArbitraryScaleFactorWithMissingResource) {
   if (!ImageSkia::IsDSFScalingInImageSkiaEnabled())
     return;
 
-  ImageSkia image(new FixedSource(
-      ImageSkiaRep(Size(100, 200), 1.0f)), Size(100, 200));
+  Canvas canvas(Size(100, 200), 1.0f, false);
+  canvas.FillRect(Rect(0, 0, 100, 200), SK_ColorRED);
+  ImageSkia image(new FixedSource(canvas.ExtractImageRep()), Size(100, 200));
 
   // Requesting 1.5f -- falls back to 2.0f, but couldn't find. It should
   // look up 1.0f and then rescale it.
@@ -525,8 +532,11 @@ TEST_F(ImageSkiaTest, UnscaledImageForArbitraryScaleFactor) {
     return;
 
   // 0.0f means unscaled.
+  Canvas canvas(Size(100, 200), 1.0f, false);
+  canvas.FillRect(Rect(0, 0, 100, 200), SK_ColorRED);
+  ImageSkiaRep origin_rep = canvas.ExtractImageRep();
   ImageSkia image(new FixedSource(
-      ImageSkiaRep(Size(100, 200), 0.0f)), Size(100, 200));
+      ImageSkiaRep(origin_rep.sk_bitmap(), 0.0f)), Size(100, 200));
 
   // Requesting 2.0f, which should return 1.0f unscaled image.
   const ImageSkiaRep& rep = image.GetRepresentation(2.0f);