Parse Drive API responses all at once in the blocking pool.

Previous implementation did the parsing of string to base::Value
on blocking pool, and that of base::Value to specific data types
either on UI thread or on yet another post to blocking pool.

The previous implementation is slightly inefficient and moreover
involves a subtle bug 284244.

BUG=284244

Review URL: https://codereview.chromium.org/442193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288017 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 11 insertions, 33 deletions

diff --git a/chrome/browser/drive/drive_api_service.cc b/chrome/browser/drive/drive_api_service.cc
index 48104ae..7fcb570 100644
--- a/chrome/browser/drive/drive_api_service.cc
+++ b/chrome/browser/drive/drive_api_service.cc
@@ -8,10 +8,7 @@
 #include <vector>
 
 #include "base/bind.h"
-#include "base/sequenced_task_runner.h"
 #include "base/strings/stringprintf.h"
-#include "base/task_runner_util.h"
-#include "base/values.h"
 #include "chrome/browser/drive/drive_api_util.h"
 #include "content/public/browser/browser_thread.h"
 #include "google_apis/drive/auth_service.h"
@@ -147,6 +144,16 @@ void ExtractOpenUrlAndRun(const std::string& app_id,
   callback.Run(GDATA_OTHER_ERROR, GURL());
 }
 
+void ExtractShareUrlAndRun(const google_apis::GetShareUrlCallback& callback,
+                           google_apis::GDataErrorCode error,
+                           scoped_ptr<google_apis::ResourceEntry> entry) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  const google_apis::Link* share_link =
+      entry ? entry->GetLinkByType(google_apis::Link::LINK_SHARE) : NULL;
+  callback.Run(error, share_link ? share_link->href() : GURL());
+}
+
 // Ignores the |entry|, and runs the |callback|.
 void EntryActionCallbackAdapter(
     const EntryActionCallback& callback,
@@ -372,7 +379,7 @@ CancelCallback DriveAPIService::GetShareUrl(
                                   wapi_url_generator_,
                                   resource_id,
                                   embed_origin,
-                                  base::Bind(&util::ParseShareUrlAndRun,
+                                  base::Bind(&ExtractShareUrlAndRun,
                                              callback)));
 }
 
diff --git a/chrome/browser/drive/drive_api_util.cc b/chrome/browser/drive/drive_api_util.cc
index 1c0d2be..9359c37 100644
--- a/chrome/browser/drive/drive_api_util.cc
+++ b/chrome/browser/drive/drive_api_util.cc
@@ -139,29 +139,6 @@ std::string CanonicalizeResourceId(const std::string& resource_id) {
 const char kDocsListScope[] = "https://docs.google.com/feeds/";
 const char kDriveAppsScope[] = "https://www.googleapis.com/auth/drive.apps";
 
-void ParseShareUrlAndRun(const google_apis::GetShareUrlCallback& callback,
-                         google_apis::GDataErrorCode error,
-                         scoped_ptr<base::Value> value) {
-  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-
-  if (!value) {
-    callback.Run(error, GURL());
-    return;
-  }
-
-  // Parsing ResourceEntry is cheap enough to do on UI thread.
-  scoped_ptr<google_apis::ResourceEntry> entry =
-      google_apis::ResourceEntry::ExtractAndParse(*value);
-  if (!entry) {
-    callback.Run(google_apis::GDATA_PARSE_ERROR, GURL());
-    return;
-  }
-
-  const google_apis::Link* share_link =
-      entry->GetLinkByType(google_apis::Link::LINK_SHARE);
-  callback.Run(error, share_link ? share_link->href() : GURL());
-}
-
 scoped_ptr<google_apis::ResourceEntry>
 ConvertFileResourceToResourceEntry(
     const google_apis::FileResource& file_resource) {
diff --git a/chrome/browser/drive/drive_api_util.h b/chrome/browser/drive/drive_api_util.h
index 291e588..90f8820 100644
--- a/chrome/browser/drive/drive_api_util.h
+++ b/chrome/browser/drive/drive_api_util.h
@@ -77,12 +77,6 @@ std::string CanonicalizeResourceId(const std::string& resource_id);
 extern const char kDocsListScope[];
 extern const char kDriveAppsScope[];
 
-// Extracts an url to the sharing dialog and returns it via |callback|. If
-// the share url doesn't exist, then an empty url is returned.
-void ParseShareUrlAndRun(const google_apis::GetShareUrlCallback& callback,
-                         google_apis::GDataErrorCode error,
-                         scoped_ptr<base::Value> value);
-
 // Converts FileResource to ResourceEntry.
 scoped_ptr<google_apis::ResourceEntry>
 ConvertFileResourceToResourceEntry(