Fixed a few places where uninitialized memory could have been read

src/core/SkValidatingReadBuffer.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkErrorInternals.h"
 #include "SkValidatingReadBuffer.h"
@@ skipping 11 matching lines @@
 
 bool SkValidatingReadBuffer::validate(bool isValid) {
     if (!fError && !isValid) {
         // When an error is found, send the read cursor to the end of the stream
         fReader.skip(fReader.available());
         fError = true;
     }
     return !fError;
 }
 
+bool SkValidatingReadBuffer::isValid() const {
+    return !fError;
+}
+
 void SkValidatingReadBuffer::setMemory(const void* data, size_t size) {
     this->validate(IsPtrAlign4(data) && (SkAlign4(size) == size));
     if (!fError) {
         fReader.setMemory(data, size);
     }
 }
 
 const void* SkValidatingReadBuffer::skip(size_t size) {
     size_t inc = SkAlign4(size);
     const void* addr = fReader.peek();
@@ skipping 216 matching lines @@
             delete obj;
             obj = NULL;
         }
     } else {
         // we must skip the remaining data
         this->skip(sizeRecorded);
         SkASSERT(false);
     }
     return obj;
 }