Implemented getBufferSubData, fixed bindTransformFeedback conformance issue.

Source/core/html/canvas/WebGL2RenderingContextBase.cpp

 // Copyright 2015 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 "config.h"
 #include "core/html/canvas/WebGL2RenderingContextBase.h"
 
 #include "bindings/core/v8/WebGLAny.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
@@ skipping 73 matching lines @@
         return;
 
     webContext()->copyBufferSubData(readTarget, writeTarget, readOffset, writeOffset, size);
 }
 
 void WebGL2RenderingContextBase::getBufferSubData(GLenum target, GLintptr offset, DOMArrayBuffer* returnedData)
 {
     if (isContextLost())
         return;
 
-    notImplemented();
+    void* mappedData = webContext()->mapBufferRange(target, offset, returnedData->byteLength(), GL_MAP_READ_BIT);
+
+    if (!mappedData)
+        return;
+
+    memcpy(returnedData->data(), mappedData, returnedData->byteLength());
+
+    webContext()->unmapBuffer(target);
 }
 
 void WebGL2RenderingContextBase::blitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter)
 {
     if (isContextLost())
         return;
 
     webContext()->blitFramebufferCHROMIUM(srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1, mask, filter);
 }
 
@@ skipping 1157 matching lines @@
         return 0;
 
     return webContext()->isTransformFeedback(feedback->object());
 }
 
 void WebGL2RenderingContextBase::bindTransformFeedback(GLenum target, WebGLTransformFeedback* feedback)
 {
     bool deleted;
     if (!checkObjectToBeBound("bindTransformFeedback", feedback, deleted))
         return;
-    if (deleted)
-        feedback = 0;
+    if (deleted) {
+        synthesizeGLError(GL_INVALID_OPERATION, "bindTransformFeedback", "attempted to bind a deleted transform feedback object");
+        return;
+    }
 
     if (target != GL_TRANSFORM_FEEDBACK) {
         synthesizeGLError(GL_INVALID_ENUM, "bindTransformFeedback", "target must be TRANSFORM_FEEDBACK");
         return;
     }
 
     m_transformFeedbackBinding = feedback;
 
     webContext()->bindTransformFeedback(target, objectOrZero(feedback));
     if (feedback)
@@ skipping 792 matching lines @@
         m_boundPixelUnpackBuffer = nullptr;
     if (m_boundTransformFeedbackBuffer == buffer)
         m_boundTransformFeedbackBuffer = nullptr;
     if (m_boundUniformBuffer == buffer)
         m_boundUniformBuffer = nullptr;
 
     WebGLRenderingContextBase::removeBoundBuffer(buffer);
 }
 
 } // namespace blink