Add PERSISTENT_MAP usage for GpuMemoryBuffers.

content/public/common/content_switches.h

Index: content/public/common/content_switches.h
diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
index a84daf37ec975019635b4a2a7da88efbe6cc04a4..550f46241c42b53a5f85f5aa22544e9cc7be235b 100644
--- a/content/public/common/content_switches.h
+++ b/content/public/common/content_switches.h
@@ -228,7 +228,8 @@ CONTENT_EXPORT extern const char kTraceUploadURL[];
 CONTENT_EXPORT extern const char kUIPrioritizeInGpuProcess[];
 CONTENT_EXPORT extern const char kUseFakeUIForMediaStream[];
 CONTENT_EXPORT extern const char kEnableNativeGpuMemoryBuffers[];
-CONTENT_EXPORT extern const char kUseImageTextureTarget[];
+CONTENT_EXPORT extern const char kMapImageTextureTarget[];
+CONTENT_EXPORT extern const char kPersistentMapImageTextureTarget[];

[reveman, 2015/05/20 14:26:08]

See my content/renderer/gpu/compositor_dependencies.h comment. I don't think a
different command line switch for each combination of format and usage is an
acceptable solution.

[danakj, 2015/05/20 17:51:14]

This is just to support partial update vs not. I agree with you, but the
compositor only uses a single format and we don't know what it is in the
embedder. This is only going as far as we need to go for supporting partial tile
updates. Please don't make me rewrite everything about choosing GpuMemoryBuffer
formats in order to implement partial tile updates. This is blocking implside
painting and I just don't see the need.

 CONTENT_EXPORT extern const char kUseMobileUserAgent[];
 CONTENT_EXPORT extern const char kUseNormalPriorityForTileTaskWorkerThreads[];
 extern const char kUseSurfaces[];