Allow default texture cache limit to be set within gyp.

Review URL: https://codereview.appspot.com/6818051

git-svn-id: http://skia.googlecode.com/svn/trunk@6177 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index b2733c2..900af8a 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -49,7 +49,7 @@
 #endif
 
 static const size_t MAX_TEXTURE_CACHE_COUNT = 2048;
-static const size_t MAX_TEXTURE_CACHE_BYTES = 96 * 1024 * 1024;
+static const size_t MAX_TEXTURE_CACHE_BYTES = GR_DEFAULT_TEXTURE_CACHE_MB_LIMIT * 1024 * 1024;
 
 static const size_t DRAW_BUFFER_VBPOOL_BUFFER_SIZE = 1 << 15;
 static const int DRAW_BUFFER_VBPOOL_PREALLOC_BUFFERS = 4;