Make GrResourceCache perf less sensitive to key length change

include/gpu/GrResourceKey.h

 
 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrResourceKey_DEFINED
 #define GrResourceKey_DEFINED
@@ skipping 28 matching lines @@
 
     /** Reset to an invalid key. */
     void reset() {
         GR_STATIC_ASSERT((uint16_t)kInvalidDomain == kInvalidDomain);
         fKey.reset(kMetaDataCnt);
         fKey[kHash_MetaDataIdx] = 0;
         fKey[kDomainAndSize_MetaDataIdx] = kInvalidDomain;
     }
 
     bool operator==(const GrResourceKey& that) const {
-        return 0 == memcmp(fKey.get(), that.fKey.get(), this->size());
+        return this->hash() == that.hash() &&
+                0 == memcmp(&fKey[kHash_MetaDataIdx + 1],
+                            &that.fKey[kHash_MetaDataIdx + 1],
+                            this->internalSize() - sizeof(uint32_t));
     }
 
     GrResourceKey& operator=(const GrResourceKey& that) {
         SkASSERT(that.isValid());
         if (this != &that) {
             size_t bytes = that.size();
             SkASSERT(SkIsAlign4(bytes));
             fKey.reset(SkToInt(bytes / sizeof(uint32_t)));
             memcpy(fKey.get(), that.fKey.get(), bytes);
             this->validate();
@@ skipping 236 matching lines @@
         fKey = that.fKey;
         return *this;
     }
 
     const GrUniqueKey& key() const { return fKey; }
 
 private:
     GrUniqueKey fKey;
 };
 #endif