Use calloc to allocate data that will be uploaded to vertex/index buffers in Chrome

BUG=chromium:454267
BUG=chromium:522315

Review URL: https://codereview.chromium.org/1300123002
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index 733c55b..b7e43d6 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -93,6 +93,7 @@
     fTextureBarrierSupport = false;
     fSupportsInstancedDraws = false;
     fFullClearIsFree = false;
+    fMustClearUploadedBufferData = false;
 
     fUseDrawInsteadOfClear = false;
 
@@ -156,6 +157,7 @@
     r.appendf("Texture Barrier Support            : %s\n", gNY[fTextureBarrierSupport]);
     r.appendf("Supports instanced draws           : %s\n", gNY[fSupportsInstancedDraws]);
     r.appendf("Full screen clear is free          : %s\n", gNY[fFullClearIsFree]);
+    r.appendf("Must clear buffer memory           : %s\n", gNY[fMustClearUploadedBufferData]);
     r.appendf("Draw Instead of Clear [workaround] : %s\n", gNY[fUseDrawInsteadOfClear]);
     r.appendf("Draw Instead of TexSubImage [workaround] : %s\n",
               gNY[fUseDrawInsteadOfPartialRenderTargetWrite]);