Use stream usage for dynamic vertex data.

src/gpu/gl/GrGLBufferImpl.cpp

Index: src/gpu/gl/GrGLBufferImpl.cpp
===================================================================
--- src/gpu/gl/GrGLBufferImpl.cpp	(revision 8124)
+++ src/gpu/gl/GrGLBufferImpl.cpp	(working copy)
@@ -16,6 +16,8 @@
 #define VALIDATE() do {} while(false)
 #endif
 

[robertphillips, 2013/03/13 15:20:54]

GR_?
Comment as to why we even have this #define?

[bsalomon, 2013/03/13 15:29:22]

It's not exposed outside this cpp so I don't think it needs a prefix.
Will add:
// GL_STREAM_DRAW triggers an optimization in Chromium's GPU 
// process where a client's vertex objects are implemented 
// as client-side-arrays on tile-deferred architectures.

+#define DYNAMIC_USAGE_PARAM GR_GL_STREAM_DRAW
+
 GrGLBufferImpl::GrGLBufferImpl(GrGpuGL* gpu, const Desc& desc, GrGLenum bufferType)
     : fDesc(desc)
     , fBufferType(bufferType)
@@ -76,7 +78,7 @@
         GL_CALL(gpu, BufferData(fBufferType,
                                 fDesc.fSizeInBytes,
                                 NULL,
-                                fDesc.fDynamic ? GR_GL_DYNAMIC_DRAW : GR_GL_STATIC_DRAW));
+                                fDesc.fDynamic ? DYNAMIC_USAGE_PARAM : GR_GL_STATIC_DRAW));
         GR_GL_CALL_RET(gpu->glInterface(),
                        fLockPtr,
                        MapBuffer(fBufferType, GR_GL_WRITE_ONLY));
@@ -111,7 +113,7 @@
         return true;
     }
     this->bind(gpu);
-    GrGLenum usage = fDesc.fDynamic ? GR_GL_DYNAMIC_DRAW : GR_GL_STATIC_DRAW;
+    GrGLenum usage = fDesc.fDynamic ? DYNAMIC_USAGE_PARAM : GR_GL_STATIC_DRAW;
 
 #if GR_GL_USE_BUFFER_DATA_NULL_HINT
     if (fDesc.fSizeInBytes == srcSizeInBytes) {