Add a parameter GR_ALWAYS_ALLOCATE_ON_HEAP to allow for only ever creating temporary buffers on the…

src/gpu/gl/GrGpuGL.cpp

Index: src/gpu/gl/GrGpuGL.cpp
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index ed8279d865a27424a4ea5a810a5cbd79e61feb2f..bd48033c8a86b4ddb0ce2c2e9743a986c7fec8d0 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -578,7 +578,11 @@ bool GrGpuGL::uploadTexData(const GrGLTexture::Desc& desc,
     size_t trimRowBytes = width * bpp;
 
     // in case we need a temporary, trimmed copy of the src pixels
+#if GR_ALWAYS_ALLOCATE_ON_HEAP
+    SkAutoMalloc tempStorage;
+#else
     SkAutoSMalloc<128 * 128> tempStorage;
+#endif
 
     // We currently lazily create MIPMAPs when the we see a draw with
     // GrTextureParams::kMipMap_FilterMode. Using texture storage requires that the
@@ -1666,7 +1670,13 @@ bool GrGpuGL::onReadPixels(GrRenderTarget* target,
 
     // determine if GL can read using the passed rowBytes or if we need
     // a scratch buffer.
+
+#if GR_ALWAYS_ALLOCATE_ON_HEAP
+    SkAutoMalloc scratch;
+#else
     SkAutoSMalloc<32 * sizeof(GrColor)> scratch;
+#endif
+
     if (rowBytes != tightRowBytes) {
         if (this->glCaps().packRowLengthSupport()) {
             SkASSERT(!(rowBytes % sizeof(GrColor)));