Add createGradient and createPattern to OffscreenCanvas2D in worker

third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.cpp

Index: third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.cpp
diff --git a/third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.cpp b/third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.cpp
index 1044ed1ab0669513f796c59cfcbdc0dee25afd90..5397f3b51a520620ce17ff729238ca3646fb8531 100644
--- a/third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.cpp
@@ -1052,7 +1052,7 @@ void BaseRenderingContext2D::drawImage(CanvasImageSource* imageSource,
             buffer->setHasExpensiveOp();
     }
 
-    if (originClean() && wouldTaintOrigin(imageSource))
+    if (originClean() && wouldTaintOrigin(imageSource, nullptr))

[Justin Novosad, 2016/04/27 19:32:25]

why no scriptState here? I realize you have not yet exposed drawImage in OCRC2D,
but OCRC2D::wouldTaintOrigin expects scriptState to never be null (no null
check).

[xlai (Olivia), 2016/04/27 19:47:49]

The call here does not invoke OCRC2D::wouldTaintOrigin, because drawImage is not
exposed in OCRC2D yet. It will only invoke either CRC2D::wouldTaintOrigin or
PaintRC2D::wouldTaintOrigin, neither of them require ScriptState*.

Once OCRC2D::wouldTaintOrigin() is completed and drawImage is exposed to OCRC2D,
this line of code will be changed as well.

         setOriginTainted();
 }
 
@@ -1089,7 +1089,7 @@ CanvasGradient* BaseRenderingContext2D::createRadialGradient(double x0, double y
     return gradient;
 }
 
-CanvasPattern* BaseRenderingContext2D::createPattern(const CanvasImageSourceUnion& imageSource, const String& repetitionType, ExceptionState& exceptionState)
+CanvasPattern* BaseRenderingContext2D::createPattern(ScriptState* scriptState, const CanvasImageSourceUnion& imageSource, const String& repetitionType, ExceptionState& exceptionState)
 {
     Pattern::RepeatMode repeatMode = CanvasPattern::parseRepetitionType(repetitionType, exceptionState);
     if (exceptionState.hadException())
@@ -1122,7 +1122,7 @@ CanvasPattern* BaseRenderingContext2D::createPattern(const CanvasImageSourceUnio
     }
     ASSERT(imageForRendering);
 
-    bool originClean = !wouldTaintOrigin(imageSourceInternal);
+    bool originClean = !wouldTaintOrigin(imageSourceInternal, scriptState);
 
     return CanvasPattern::create(imageForRendering.release(), repeatMode, originClean);
 }