Bug 1205900 - Compare context and canvas element sizes before extracting the data. r=gwright

dom/canvas/CanvasRenderingContext2D.cpp

@@ -1472,7 +1472,6 @@ CanvasRenderingContext2D::EnsureTarget(RenderingMode aRenderingMode)
   return mode;
 }
 
-#ifdef DEBUG
 int32_t
 CanvasRenderingContext2D::GetWidth() const
 {
@@ -1484,7 +1483,6 @@ CanvasRenderingContext2D::GetHeight() const
 {
   return mHeight;
 }
-#endif
 
 NS_IMETHODIMP
 CanvasRenderingContext2D::SetDimensions(int32_t width, int32_t height)

dom/canvas/CanvasRenderingContext2D.h

@@ -418,10 +418,9 @@ public:
 
   nsresult Redraw();
 
-#ifdef DEBUG
-    virtual int32_t GetWidth() const override;
-    virtual int32_t GetHeight() const override;
-#endif
+  virtual int32_t GetWidth() const override;
+  virtual int32_t GetHeight() const override;
+
   // nsICanvasRenderingContextInternal
   /**
     * Gets the pres shell from either the canvas element or the doc shell

dom/canvas/WebGLContext.cpp

@@ -480,7 +480,6 @@ WebGLContext::SetContextOptions(JSContext* cx, JS::Handle<JS::Value> options)
     return NS_OK;
 }
 
-#ifdef DEBUG
 int32_t
 WebGLContext::GetWidth() const
 {
@@ -492,7 +491,6 @@ WebGLContext::GetHeight() const
 {
     return mHeight;
 }
-#endif
 
 /* So there are a number of points of failure here. We might fail based
  * on EGL vs. WGL, or we might fail to alloc a too-large size, or we

dom/canvas/WebGLContext.h

@@ -215,10 +215,9 @@ public:
     NS_DECL_NSIDOMWEBGLRENDERINGCONTEXT
 
     // nsICanvasRenderingContextInternal
-#ifdef DEBUG
     virtual int32_t GetWidth() const override;
     virtual int32_t GetHeight() const override;
-#endif
+
     NS_IMETHOD SetDimensions(int32_t width, int32_t height) override;
     NS_IMETHOD InitializeWithSurface(nsIDocShell*, gfxASurface*, int32_t,
                                      int32_t) override

dom/canvas/nsICanvasRenderingContextInternal.h

@@ -80,11 +80,9 @@ public:
     return mCanvasElement;
   }
 
-#ifdef DEBUG
-    // Useful for testing
-    virtual int32_t GetWidth() const = 0;
-    virtual int32_t GetHeight() const = 0;
-#endif
+  // Dimensions of the canvas, in pixels.
+  virtual int32_t GetWidth() const = 0;
+  virtual int32_t GetHeight() const = 0;
 
   // Sets the dimensions of the canvas, in pixels.  Called
   // whenever the size of the element changes.

dom/html/HTMLCanvasElement.cpp

@@ -669,18 +669,19 @@ HTMLCanvasElement::ToBlob(JSContext* aCx,
     return;
   }
 
-#ifdef DEBUG
   if (mCurrentContext) {
     // We disallow canvases of width or height zero, and set them to 1, so
     // we will have a discrepancy with the sizes of the canvas and the context.
     // That discrepancy is OK, the rest are not.
     nsIntSize elementSize = GetWidthHeight();
-    MOZ_ASSERT(elementSize.width == mCurrentContext->GetWidth() ||
-               (elementSize.width == 0 && mCurrentContext->GetWidth() == 1));
-    MOZ_ASSERT(elementSize.height == mCurrentContext->GetHeight() ||
-               (elementSize.height == 0 && mCurrentContext->GetHeight() == 1));
+    if ((elementSize.width != mCurrentContext->GetWidth() &&
+         (elementSize.width != 0 || mCurrentContext->GetWidth() != 1)) ||
+        (elementSize.height != mCurrentContext->GetHeight() &&
+         (elementSize.height != 0 || mCurrentContext->GetHeight() != 1))) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+    }
   }
-#endif
 
   uint8_t* imageBuffer = nullptr;
   int32_t format = 0;