Begin atlasing

src/image/SkSurface_Gpu.cpp

Index: src/image/SkSurface_Gpu.cpp
diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index a34b774397b11e9539d5c67264fc24bbe1d4b426..550e197fe50e653b3dc75cc8ce6f99658557a5bf 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -14,7 +14,7 @@ class SkSurface_Gpu : public SkSurface_Base {
 public:
     SK_DECLARE_INST_COUNT(SkSurface_Gpu)
 
-    SkSurface_Gpu(GrRenderTarget*, bool cached, TextRenderMode trm);
+    SkSurface_Gpu(GrRenderTarget*, bool cached, TextRenderMode trm, bool clear);
     virtual ~SkSurface_Gpu();
 
     virtual SkCanvas* onNewCanvas() SK_OVERRIDE;
@@ -33,14 +33,15 @@ private:
 
 ///////////////////////////////////////////////////////////////////////////////
 
-SkSurface_Gpu::SkSurface_Gpu(GrRenderTarget* renderTarget, bool cached, TextRenderMode trm)
+SkSurface_Gpu::SkSurface_Gpu(GrRenderTarget* renderTarget, bool cached, TextRenderMode trm,
+                             bool clear)
         : INHERITED(renderTarget->width(), renderTarget->height()) {
     int flags = 0;
     flags |= cached ? SkGpuDevice::kCached_Flag : 0;
     flags |= (kDistanceField_TextRenderMode == trm) ? SkGpuDevice::kDFFonts_Flag : 0;
     fDevice = SkGpuDevice::Create(renderTarget, flags);
 
-    if (kRGB_565_GrPixelConfig != renderTarget->config()) {
+    if (kRGB_565_GrPixelConfig != renderTarget->config() && clear) {
         fDevice->clear(0x0);
     }
 }
@@ -101,11 +102,11 @@ void SkSurface_Gpu::onDiscard() {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-SkSurface* SkSurface::NewRenderTargetDirect(GrRenderTarget* target, TextRenderMode trm) {
+SkSurface* SkSurface::NewRenderTargetDirect(GrRenderTarget* target, TextRenderMode trm, bool clear) {
     if (NULL == target) {
         return NULL;
     }
-    return SkNEW_ARGS(SkSurface_Gpu, (target, false, trm));
+    return SkNEW_ARGS(SkSurface_Gpu, (target, false, trm, clear));
 }
 
 SkSurface* SkSurface::NewRenderTarget(GrContext* ctx, const SkImageInfo& info, int sampleCount,
@@ -126,7 +127,7 @@ SkSurface* SkSurface::NewRenderTarget(GrContext* ctx, const SkImageInfo& info, i
         return NULL;
     }
 
-    return SkNEW_ARGS(SkSurface_Gpu, (tex->asRenderTarget(), false, trm));
+    return SkNEW_ARGS(SkSurface_Gpu, (tex->asRenderTarget(), false, trm, true));
 }
 
 SkSurface* SkSurface::NewScratchRenderTarget(GrContext* ctx, const SkImageInfo& info,
@@ -148,5 +149,5 @@ SkSurface* SkSurface::NewScratchRenderTarget(GrContext* ctx, const SkImageInfo&
         return NULL;
     }
 
-    return SkNEW_ARGS(SkSurface_Gpu, (tex->asRenderTarget(), true, trm));
+    return SkNEW_ARGS(SkSurface_Gpu, (tex->asRenderTarget(), true, trm, true));
 }