gpudevice should never allocate pixels for its backend

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/GrBicubicEffect.h"
@@ skipping 137 matching lines @@
 static SkBitmap make_bitmap(GrContext* context, GrRenderTarget* renderTarget) {
     bool isOpaque;
     SkBitmap::Config config = grConfig2skConfig(renderTarget->config(), &isOpaque);
 
     SkBitmap bitmap;
     bitmap.setConfig(config, renderTarget->width(), renderTarget->height(), 0,
                      isOpaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
     return bitmap;
 }
 
+/*
+ *  Calling SkBitmapDevice with individual params asks it to allocate pixel memory.
+ *  We never want that, so we always need to call it with a bitmap argument
+ *  (which says take my allocate (or lack thereof)).
+ *
+ *  This is a REALLY good reason to finish the clean-up of SkBaseDevice, and have
+ *  SkGpuDevice inherit from that instead of SkBitmapDevice.
+ */
+static SkBitmap make_bitmap(SkBitmap::Config config, int width, int height, bool isOpaque) {
+    SkBitmap bm;
+    bm.setConfig(config, width, height, isOpaque);
+    return bm;
+}
+
 SkGpuDevice* SkGpuDevice::Create(GrSurface* surface) {
     SkASSERT(NULL != surface);
     if (NULL == surface->asRenderTarget() || NULL == surface->getContext()) {
         return NULL;
     }
     if (surface->asTexture()) {
         return SkNEW_ARGS(SkGpuDevice, (surface->getContext(), surface->asTexture()));
     } else {
         return SkNEW_ARGS(SkGpuDevice, (surface->getContext(), surface->asRenderTarget()));
     }
@@ skipping 35 matching lines @@
     SkPixelRef* pr = SkNEW_ARGS(SkGrPixelRef, (surface, cached));
 
     this->setPixelRef(pr, 0)->unref();
 }
 
 SkGpuDevice::SkGpuDevice(GrContext* context,
                          SkBitmap::Config config,
                          int width,
                          int height,
                          int sampleCount)
-    : SkBitmapDevice(config, width, height, false /*isOpaque*/) {
+    : SkBitmapDevice(make_bitmap(config, width, height, false /*isOpaque*/)) {
 
     fDrawProcs = NULL;
 
     fContext = context;
     fContext->ref();
 
     fRenderTarget = NULL;
     fNeedClear = false;
 
     if (config != SkBitmap::kRGB_565_Config) {
@@ skipping 1657 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;
 }