Backed out changeset 9a2aab98a8d0 (bug 982480) for reftest failures.

content/canvas/public/nsICanvasRenderingContextInternal.h

@@ -97,7 +97,6 @@ public:
   // dst alpha is always 1.0.  If this is never called, the context
   // defaults to false (not opaque).
   NS_IMETHOD SetIsOpaque(bool isOpaque) = 0;
-  virtual bool GetIsOpaque() = 0;
 
   // Invalidate this context and release any held resources, in preperation
   // for possibly reinitializing with SetDimensions/InitializeWithSurface.

content/canvas/src/CanvasRenderingContext2D.cpp

@@ -988,10 +988,6 @@ CanvasRenderingContext2D::SetIsOpaque(bool isOpaque)
     ClearTarget();
   }
 
-  if (mOpaque) {
-    EnsureTarget();
-  }
-
   return NS_OK;
 }
 
@@ -1066,8 +1062,6 @@ CanvasRenderingContext2D::SetContextOptions(JSContext* aCx, JS::Handle<JS::Value
     mForceSoftware = attributes.mWillReadFrequently;
   }
 
-  SetIsOpaque(!attributes.mAlpha);
-
   return NS_OK;
 }
 
@@ -3813,30 +3807,6 @@ CanvasRenderingContext2D::GetImageDataArray(JSContext* aCx,
   // inherited from Thebes canvas and is no longer true
   uint8_t* dst = data + dstWriteRect.y * (aWidth * 4) + dstWriteRect.x * 4;
 
-  if (mOpaque) {
-    for (int32_t j = 0; j < dstWriteRect.height; ++j) {
-      for (int32_t i = 0; i < dstWriteRect.width; ++i) {
-        // XXX Is there some useful swizzle MMX we can use here?
-#if MOZ_LITTLE_ENDIAN
-        uint8_t b = *src++;
-        uint8_t g = *src++;
-        uint8_t r = *src++;
-        src++;
-#else
-        src++;
-        uint8_t r = *src++;
-        uint8_t g = *src++;
-        uint8_t b = *src++;
-#endif
-        *dst++ = r;
-        *dst++ = g;
-        *dst++ = b;
-        *dst++ = 255;
-      }
-      src += srcStride - (dstWriteRect.width * 4);
-      dst += (aWidth * 4) - (dstWriteRect.width * 4);
-    }
-  } else
   for (int32_t j = 0; j < dstWriteRect.height; ++j) {
     for (int32_t i = 0; i < dstWriteRect.width; ++i) {
       // XXX Is there some useful swizzle MMX we can use here?

content/canvas/src/CanvasRenderingContext2D.h

@@ -408,7 +408,6 @@ public:
   { EnsureTarget(); return mTarget->Snapshot(); }
 
   NS_IMETHOD SetIsOpaque(bool isOpaque) MOZ_OVERRIDE;
-  bool GetIsOpaque() MOZ_OVERRIDE { return mOpaque; }
   NS_IMETHOD Reset() MOZ_OVERRIDE;
   already_AddRefed<CanvasLayer> GetCanvasLayer(nsDisplayListBuilder* aBuilder,
                                                CanvasLayer *aOldLayer,

content/canvas/src/WebGLContext.h

@@ -178,7 +178,6 @@ public:
     mozilla::TemporaryRef<mozilla::gfx::SourceSurface> GetSurfaceSnapshot() MOZ_OVERRIDE;
 
     NS_IMETHOD SetIsOpaque(bool b) MOZ_OVERRIDE { return NS_OK; };
-    bool GetIsOpaque() MOZ_OVERRIDE { return false; }
     NS_IMETHOD SetContextOptions(JSContext* aCx,
                                  JS::Handle<JS::Value> aOptions) MOZ_OVERRIDE;
 

content/canvas/test/test_canvas.html

@@ -21577,24 +21577,6 @@ function test_linedash() {
 }
 </script>
 
-<p>Canvas test: test_opaque</p>
-<canvas id="c688" width="150" height="50"></canvas>
-<script type="text/javascript">
-
-function test_opaque() {
-  var c = document.getElementById("c688");
-  var ctx = c.getContext("2d", {alpha: false});
-  ctx.fillStyle = "green";
-  ctx.fillRect(0,0,10,10);
-  ctx.fillStyle = "rgba(255,0,0,.5)";
-  ctx.fillRect(10,0,10,10);
-
-  isPixel(ctx, 20, 20, 0, 0, 0, 255, 0);
-  isPixel(ctx, 5, 5, 0, 128, 0, 255, 0);
-  isPixel(ctx, 15, 5, 128, 0, 0, 255, 0);
-}
-</script>
-
 <script>
 
 function asyncTestsDone() {
@@ -24891,12 +24873,6 @@ function runTests() {
   throw e;
   ok(false, "unexpected exception thrown in: test_linedash");
  }
-try {
-  test_opaque();
- } catch(e) {
-  throw e;
-  ok(false, "unexpected exception thrown in: test_opaque");
- }
  try {
   // run this test last since it replaces the getContext method
   test_type_replace();

content/html/content/src/HTMLCanvasElement.cpp

@@ -903,10 +903,6 @@ HTMLCanvasElement::GetContextAtIndex(int32_t index)
 bool
 HTMLCanvasElement::GetIsOpaque()
 {
-  if (mCurrentContext) {
-    return mCurrentContext->GetIsOpaque();
-  }
-
   return HasAttr(kNameSpaceID_None, nsGkAtoms::moz_opaque);
 }
 

dom/webidl/CanvasRenderingContext2D.webidl

@@ -16,8 +16,6 @@ enum CanvasWindingRule { "nonzero", "evenodd" };
 dictionary ContextAttributes2D {
   // whether or not we're planning to do a lot of readback operations
   boolean willReadFrequently = false;
-  // signal if the canvas contains an alpha channel
-  boolean alpha = true;
 };
 
 dictionary HitRegionOptions {