Begin atlasing

include/core/SkSurface.h

Index: include/core/SkSurface.h
diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index 68d4702cb51d6f9bfdf8b73d01e1f2d5d3221094..cb5133ae003e4d89de0f2f376b749977aee715f4 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -77,18 +77,29 @@ public:
         kDistanceField_TextRenderMode,
     };
 
+    enum RenderTargetFlags {
+        kNone_RenderTargetFlag      = 0x0,
+        /*
+         * By default a RenderTarget-based surface will be cleared on creation.
+         * Pass in this flag to prevent the clear from happening.
+         */
+        kDontClear_RenderTargetFlag = 0x01,
+    };
+
     /**
      *  Return a new surface using the specified render target.
      */
     static SkSurface* NewRenderTargetDirect(GrRenderTarget*,
-                                            TextRenderMode trm = kStandard_TextRenderMode);
+                                            TextRenderMode trm = kStandard_TextRenderMode,
+                                            RenderTargetFlags flags = kNone_RenderTargetFlag);
 
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface.
      */
     static SkSurface* NewRenderTarget(GrContext*, const SkImageInfo&, int sampleCount = 0,
-                                      TextRenderMode trm = kStandard_TextRenderMode);
+                                      TextRenderMode trm = kStandard_TextRenderMode,
+                                      RenderTargetFlags flags = kNone_RenderTargetFlag);
 
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
@@ -103,7 +114,8 @@ public:
      *  budget.
      */
     static SkSurface* NewScratchRenderTarget(GrContext*, const SkImageInfo&, int sampleCount = 0,
-                                             TextRenderMode trm = kStandard_TextRenderMode);
+                                             TextRenderMode trm = kStandard_TextRenderMode,
+                                             RenderTargetFlags flags = kNone_RenderTargetFlag);
 
     int width() const { return fWidth; }
     int height() const { return fHeight; }