Content verification: Don't fail on non-existence.

extensions/browser/content_hash_reader.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/content_hash_reader.h"
 
 #include "base/base64.h"
 #include "base/file_util.h"
 #include "base/json/json_reader.h"
 #include "base/metrics/histogram.h"
@@ skipping 17 matching lines @@
                                      const base::Version& extension_version,
                                      const base::FilePath& extension_root,
                                      const base::FilePath& relative_path,
                                      const ContentVerifierKey& key)
     : extension_id_(extension_id),
       extension_version_(extension_version.GetString()),
       extension_root_(extension_root),
       relative_path_(relative_path),
       key_(key),
       status_(NOT_INITIALIZED),
+      content_exists_(false),
       have_verified_contents_(false),
       have_computed_hashes_(false),
       block_size_(0) {
 }
 
 ContentHashReader::~ContentHashReader() {
 }
 
 bool ContentHashReader::Init() {
   base::ElapsedTimer timer;
   DCHECK_EQ(status_, NOT_INITIALIZED);
   status_ = FAILURE;
   base::FilePath verified_contents_path =
       file_util::GetVerifiedContentsPath(extension_root_);
 
+  // Check that this is a valid resource to verify (i.e., it exists).
+  base::FilePath content_path = extension_root_.Append(relative_path_);
+  if (!base::PathExists(content_path))
+    return false;
+
+  content_exists_ = true;
+
   if (!base::PathExists(verified_contents_path))
     return false;
 
   verified_contents_.reset(new VerifiedContents(key_.data, key_.size));
   if (!verified_contents_->InitFrom(verified_contents_path, false) ||
       !verified_contents_->valid_signature() ||
       !verified_contents_->version().Equals(extension_version_) ||
       verified_contents_->extension_id() != extension_id_)
     return false;
 
@@ skipping 47 matching lines @@
   DCHECK(block_index >= 0);
 
   if (static_cast<unsigned>(block_index) >= hashes_.size())
     return false;
   *result = &hashes_[block_index];
 
   return true;
 }
 
 }  // namespace extensions