Add support to dump font cache texture for debug purposes

R=robertphillips@google.com, bsalomon@google.com

Author: jvanverth@google.com

Review URL: https://codereview.chromium.org/25736002

git-svn-id: http://skia.googlecode.com/svn/trunk@11579 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrAtlas.cpp b/src/gpu/GrAtlas.cpp
index 70fe3e0..9784e83 100644
--- a/src/gpu/GrAtlas.cpp
+++ b/src/gpu/GrAtlas.cpp
@@ -179,7 +179,13 @@
     if (NULL == fTexture) {
         // TODO: Update this to use the cache rather than directly creating a texture.
         GrTextureDesc desc;
+#ifdef SK_DEVELOPER
+        // RenderTarget so we can read the pixels to dump them
+        desc.fFlags = kDynamicUpdate_GrTextureFlagBit|kRenderTarget_GrTextureFlagBit
+                                                     |kNoStencil_GrTextureFlagBit;
+#else
         desc.fFlags = kDynamicUpdate_GrTextureFlagBit;
+#endif
         desc.fWidth = GR_ATLAS_TEXTURE_WIDTH;
         desc.fHeight = GR_ATLAS_TEXTURE_HEIGHT;
         desc.fConfig = fPixelConfig;
@@ -205,6 +211,7 @@
 }
 
 bool GrAtlasMgr::removeUnusedPlots(GrAtlas* atlas) {
+
     // GrPlot** is used so that the head element can be easily
     // modified when the first element is deleted
     GrPlot** plotRef = &atlas->fPlots;