Add caps overrides to GMs

include/gpu/GrContextOptions.h

Index: include/gpu/GrContextOptions.h
diff --git a/include/gpu/GrContextOptions.h b/include/gpu/GrContextOptions.h
index d78ac6cc5689d443948cba008917e383b31efb9b..686d6a9ac0eb5714dbe5f8cea01a72cfb4d3701e 100644
--- a/include/gpu/GrContextOptions.h
+++ b/include/gpu/GrContextOptions.h
@@ -11,14 +11,24 @@
 #include "SkTypes.h"
 
 struct GrContextOptions {
-    GrContextOptions() : fDrawPathToCompressedTexture(false), fSuppressPrints(false) {}
+    GrContextOptions()
+        : fDrawPathToCompressedTexture(false)
+        , fSuppressPrints(false)
+        , fMaxTextureSizeOverride(SK_MaxS32) {}
 
     // EXPERIMENTAL
     // May be removed in the future, or may become standard depending
     // on the outcomes of a variety of internal tests.
     bool fDrawPathToCompressedTexture;
+
     // Suppress prints for the GrContext.
     bool fSuppressPrints;
+
+    /** Overrides: These options override feature detection using backend API queries. These
+        overrides can only reduce the feature set or limits, never increase them beyond the
+        detected values. */
+
+    int fMaxTextureSizeOverride;
 };
 
 #endif