Fixing issues found by fuzzer

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 76 matching lines @@
 }
 
 void SkValidatingReadBuffer::readString(SkString* string) {
     const size_t len = this->readInt();
     const void* ptr = fReader.peek();
     const char* cptr = (const char*)ptr;
 
     // skip over the string + '\0' and then pad to a multiple of 4
     const size_t alignedSize = SkAlign4(len + 1);
     this->skip(alignedSize);
-    this->validate(cptr[len] == '\0');
+    if (!fError) {
+        this->validate(cptr[len] == '\0');
+    }
     if (!fError) {
         string->set(cptr, len);
     }
 }
 
 void* SkValidatingReadBuffer::readEncodedString(size_t* length, SkPaint::TextEncoding encoding) {
-    const int32_t encodingType = fReader.readInt();
+    const int32_t encodingType = this->readInt();
     this->validate(encodingType == encoding);
     *length = this->readInt();
     const void* ptr = this->skip(SkAlign4(*length));
     void* data = NULL;
     if (!fError) {
         data = sk_malloc_throw(*length);
         memcpy(data, ptr, *length);
     }
     return data;
 }
 
 void SkValidatingReadBuffer::readPoint(SkPoint* point) {
-    point->fX = fReader.readScalar();
-    point->fY = fReader.readScalar();
+    point->fX = this->readScalar();
+    point->fY = this->readScalar();
 }
 
 void SkValidatingReadBuffer::readMatrix(SkMatrix* matrix) {
     size_t size = 0;
     if (!fError) {
         size = matrix->readFromMemory(fReader.peek(), fReader.available());
         this->validate((SkAlign4(size) == size) && (0 != size));
     }
     if (!fError) {
         (void)this->skip(size);
@@ skipping 127 matching lines @@
             delete obj;
             obj = NULL;
         }
     } else {
         // we must skip the remaining data
         this->skip(sizeRecorded);
         SkASSERT(false);
     }
     return obj;
 }