Add can-ignore-rect hint to clear call

src/gpu/SkGpuDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuDevice.h"
 
 #include "effects/GrTextureDomainEffect.h"
@@ skipping 530 matching lines @@
     if (NULL == fRenderTarget) {
         return SkBitmap::kNo_Config;
     }
 
     bool isOpaque;
     return grConfig2skConfig(fRenderTarget->config(), &isOpaque);
 }
 
 void SkGpuDevice::clear(SkColor color) {
     SkIRect rect = SkIRect::MakeWH(this->width(), this->height());
-    fContext->clear(&rect, SkColor2GrColor(color), fRenderTarget);
+    fContext->clear(&rect, SkColor2GrColor(color), true, fRenderTarget);
     fNeedClear = false;
 }
 
 void SkGpuDevice::drawPaint(const SkDraw& draw, const SkPaint& paint) {
     CHECK_SHOULD_DRAW(draw, false);
 
     GrPaint grPaint;
     if (!skPaint2GrPaintShader(this, paint, true, &grPaint)) {
         return;
     }
@@ skipping 253 matching lines @@
     if (NULL == mask->texture()) {
         return false;
     }
 
     GrTexture* maskTexture = mask->texture();
     SkRect clipRect = SkRect::MakeWH(maskRect.width(), maskRect.height());
 
     GrContext::AutoRenderTarget art(context, maskTexture->asRenderTarget());
     GrContext::AutoClip ac(context, clipRect);
 
-    context->clear(NULL, 0x0);
+    context->clear(NULL, 0x0, true);
 
     GrPaint tempPaint;
     if (doAA) {
         tempPaint.setAntiAlias(true);
         // AA uses the "coverage" stages on GrDrawTarget. Coverage with a dst
         // blend coeff of zero requires dual source blending support in order
         // to properly blend partially covered pixels. This means the AA
         // code path may not be taken. So we use a dst blend coeff of ISA. We
         // could special case AA draws to a dst surface with known alpha=0 to
         // use a zero dst coeff when dual source blending isn't available.
@@ skipping 1015 matching lines @@
                          GrTexture* texture,
                          bool needClear)
     : SkBitmapDevice(make_bitmap(context, texture->asRenderTarget())) {
 
     SkASSERT(texture && texture->asRenderTarget());
     // This constructor is called from onCreateCompatibleDevice. It has locked the RT in the texture
     // cache. We pass true for the third argument so that it will get unlocked.
     this->initFromRenderTarget(context, texture->asRenderTarget(), true);
     fNeedClear = needClear;
 }