We can reuse the variable which is already declared.

Source/core/html/canvas/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 970 matching lines @@
         return;
     }
     GraphicsContext* c = drawingContext();
     if (!c) {
         return;
     }
     if (!state().m_invertibleCTM) {
         return;
     }
     FloatRect clipBounds;
-    if (!drawingContext()->getTransformedClipBounds(&clipBounds)) {
+    if (!c->getTransformedClipBounds(&clipBounds)) {
         return;
     }
 
     // If gradient size is zero, then paint nothing.
     Gradient* gradient = c->fillGradient();
     if (gradient && gradient->isZeroSize()) {
         return;
     }
 
     WindRule windRule = c->fillRule();
@@ skipping 261 matching lines @@
 {
     if (!validateRectForCanvas(x, y, width, height))
         return;
 
     GraphicsContext* c = drawingContext();
     if (!c)
         return;
     if (!state().m_invertibleCTM)
         return;
     FloatRect clipBounds;
-    if (!drawingContext()->getTransformedClipBounds(&clipBounds))
+    if (!c->getTransformedClipBounds(&clipBounds))
         return;
 
     // from the HTML5 Canvas spec:
     // If x0 = x1 and y0 = y1, then the linear gradient must paint nothing
     // If x0 = x1 and y0 = y1 and r0 = r1, then the radial gradient must paint nothing
     Gradient* gradient = c->fillGradient();
     if (gradient && gradient->isZeroSize())
         return;
 
     FloatRect rect(x, y, width, height);
@@ skipping 316 matching lines @@
 
 static void drawImageToContext(Image* image, GraphicsContext* context, const FloatRect& dest, const FloatRect& src, CompositeOperator op)
 {
     context->drawImage(image, dest, src, op);
 }
 
 template<class T> void  CanvasRenderingContext2D::fullCanvasCompositedDrawImage(T* image, const FloatRect& dest, const FloatRect& src, CompositeOperator op)
 {
     ASSERT(isFullCanvasCompositeMode(op));
 
-    drawingContext()->beginLayer(1, op);
-    drawImageToContext(image, drawingContext(), dest, src, CompositeSourceOver);
-    drawingContext()->endLayer();
+    GraphicsContext* c = drawingContext();
+    c->beginLayer(1, op);
+    drawImageToContext(image, c, dest, src, CompositeSourceOver);
+    c->endLayer();
 }
 
 static void fillPrimitive(const FloatRect& rect, GraphicsContext* context)
 {
     context->fillRect(rect);
 }
 
 static void fillPrimitive(const Path& path, GraphicsContext* context)
 {
     context->fillPath(path);
@@ skipping 798 matching lines @@
     c->setAlphaAsFloat(1.0);
     c->clearShadow();
     c->setCompositeOperation(CompositeSourceOver, blink::WebBlendModeNormal);
     c->drawFocusRing(path, focusRingWidth, focusRingOutline, focusRingColor);
     c->restore();
 
     didDraw(dirtyRect);
 }
 
 } // namespace WebCore