Add createGradient and createPattern to OffscreenCanvas2D in worker

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/canvas2d/BaseRenderingContext2D.h"
 
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ExceptionStatePlaceholder.h"
 #include "core/css/parser/CSSParser.h"
@@ skipping 1034 matching lines @@
 
     if (imageSize.width() * imageSize.height() > width() * height() * ExpensiveCanvasHeuristicParameters::ExpensiveImageSizeRatio)
         isExpensive = true;
 
     if (isExpensive) {
         ImageBuffer* buffer = imageBuffer();
         if (buffer)
             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();
 }
 
 void BaseRenderingContext2D::clearCanvas()
 {
     FloatRect canvasRect(0, 0, width(), height());
     checkOverdraw(canvasRect, 0, CanvasRenderingContext2DState::NoImage, ClipFill);
     SkCanvas* c = drawingCanvas();
     if (c)
         c->clear(hasAlpha() ? SK_ColorTRANSPARENT : SK_ColorBLACK);
@@ skipping 16 matching lines @@
 {
     if (r0 < 0 || r1 < 0) {
         exceptionState.throwDOMException(IndexSizeError, String::format("The %s provided is less than 0.", r0 < 0 ? "r0" : "r1"));
         return nullptr;
     }
 
     CanvasGradient* gradient = CanvasGradient::create(FloatPoint(x0, y0), r0, FloatPoint(x1, y1), r1);
     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())
         return nullptr;
 
     SourceImageStatus status;
     CanvasImageSource* imageSourceInternal = toImageSourceInternal(imageSource, exceptionState);
     if (!imageSourceInternal)
         return nullptr;
     FloatSize defaultObjectSize(width(), height());
@@ skipping 12 matching lines @@
         imageForRendering = Image::nullImage();
         break;
     case IncompleteSourceImageStatus:
         return nullptr;
     default:
         ASSERT_NOT_REACHED();
         return nullptr;
     }
     ASSERT(imageForRendering);
 
-    bool originClean = !wouldTaintOrigin(imageSourceInternal);
+    bool originClean = !wouldTaintOrigin(imageSourceInternal, scriptState);
 
     return CanvasPattern::create(imageForRendering.release(), repeatMode, originClean);
 }
 
 bool BaseRenderingContext2D::computeDirtyRect(const FloatRect& localRect, SkIRect* dirtyRect)
 {
     SkIRect clipBounds;
     if (!drawingCanvas()->getClipDeviceBounds(&clipBounds))
         return false;
     return computeDirtyRect(localRect, clipBounds, dirtyRect);
@@ skipping 250 matching lines @@
 
     imageBuffer()->willOverwriteCanvas();
 }
 
 DEFINE_TRACE(BaseRenderingContext2D)
 {
     visitor->trace(m_stateStack);
 }
 
 } // namespace blink