Add texture create/upload stats and make nanobench have explicit gpu stats flag

Review URL: https://codereview.chromium.org/891973002
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index 1566aab..67637e7 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -74,6 +74,12 @@
     if (!this->caps()->reuseScratchTextures() && !isRT) {
         tex->cacheAccess().removeScratchKey();
     }
+    if (tex) {
+        fStats.incTextureCreates();
+        if (srcData) {
+            fStats.incTextureUploads();
+        }
+    }
     return tex;
 }
 
@@ -203,8 +209,12 @@
                                GrPixelConfig config, const void* buffer,
                                size_t rowBytes) {
     this->handleDirtyContext();
-    return this->onWriteTexturePixels(texture, left, top, width, height,
-                                      config, buffer, rowBytes);
+    if (this->onWriteTexturePixels(texture, left, top, width, height,
+                                   config, buffer, rowBytes)) {
+        fStats.incTextureUploads();
+        return true;
+    }
+    return false;
 }
 
 void GrGpu::resolveRenderTarget(GrRenderTarget* target) {