Remove (Get|Set)LargestChangestamp from Resource Metadata.

We have stopped using (Get|Set)LargestChangestamp in favor of
(Get|Set)StartPageToken. This CL removes the code and fixes the UI
to display the start page token instead.

We leave (Get|Set)LargestChangestamp in resource metadata storage to
facilitate DB upgrades, where we write the existing largest changestamp
to the start page token field.

Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I57c8f61e3914cdfd3ea15046c8551f0456f9e636
Reviewed-on: https://chromium-review.googlesource.com/1071149Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Kazuhiro Inaba <kinaba@chromium.org>
Commit-Queue: Stuart Langley <slangley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561623}

chrome/browser/resources/chromeos/drive_internals.html

@@ -44,8 +44,8 @@
       <span id="reset-status-text"></span>
     </div>
     <ul>
-      <li>Local Changestamp:
-        <span id="account-largest-changestamp-local"></span>
+      <li>Local Start Page Token:
+        <span id="account-start-page-token-local"></span>
       </li>
       <li>Local Free Space:
         <span id="local-storage-freespace"></span> MB

chrome/browser/resources/chromeos/drive_internals.js

@@ -190,10 +190,10 @@ function updateAppList(appList) {
  * @param {Object} localMetadata Dictionary describing account metadata.
  */
 function updateLocalMetadata(localMetadata) {
-  var changestamp = localMetadata['account-largest-changestamp-local'];
+  var startPageToken = localMetadata['account-start-page-token-local'];
 
-  $('account-largest-changestamp-local').textContent = changestamp.toString() +
-      (changestamp > 0 ? ' (loaded)' : ' (not loaded)') +
+  $('account-largest-changestamp-local').textContent = startPageToken +
+      (startPageToken ? ' (loaded)' : ' (not loaded)') +
       (localMetadata['account-metadata-refreshing'] ? ' (refreshing)' : '');
 }
 

chrome/browser/ui/webui/chromeos/drive_internals_ui.cc

@@ -555,8 +555,8 @@ void DriveInternalsWebUIHandler::OnGetFilesystemMetadataForLocal(
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   base::DictionaryValue local_metadata;
-  local_metadata.SetDouble("account-largest-changestamp-local",
-                           metadata.largest_changestamp);
+  local_metadata.SetString("account-start-page-token-local",
+                           metadata.start_page_token);
   local_metadata.SetBoolean("account-metadata-refreshing", metadata.refreshing);
   web_ui()->CallJavascriptFunctionUnsafe("updateLocalMetadata", local_metadata);
 }

components/drive/chromeos/file_system.cc

@@ -181,13 +181,13 @@ void RunIsMountedCallback(const IsMountedCallback& callback,
 
 // Callback for ResourceMetadata::GetLargestChangestamp.
 // |callback| must not be null.
-void OnGetLargestChangestamp(FileSystemMetadata metadata,  // Will be modified.
+void OnGetStartPageToken(FileSystemMetadata metadata,  // Will be modified.
                          const GetFilesystemMetadataCallback& callback,
-                             const int64_t* largest_changestamp,
+                         const std::string* start_page_token,
                          FileError error) {
   DCHECK(callback);
 
-  metadata.largest_changestamp = *largest_changestamp;
+  metadata.start_page_token = *start_page_token;
   callback.Run(metadata);
 }
 
@@ -891,17 +891,13 @@ void FileSystem::GetMetadata(
   metadata.last_update_check_time = last_update_check_time_;
   metadata.last_update_check_error = last_update_check_error_;
 
-  int64_t* largest_changestamp = new int64_t(0);
+  std::string* start_page_token = new std::string();
   base::PostTaskAndReplyWithResult(
-      blocking_task_runner_.get(),
-      FROM_HERE,
-      base::Bind(&internal::ResourceMetadata::GetLargestChangestamp,
-                 base::Unretained(resource_metadata_),
-                 largest_changestamp),
-      base::Bind(&OnGetLargestChangestamp,
-                 metadata,
-                 callback,
-                 base::Owned(largest_changestamp)));
+      blocking_task_runner_.get(), FROM_HERE,
+      base::Bind(&internal::ResourceMetadata::GetStartPageToken,
+                 base::Unretained(resource_metadata_), start_page_token),
+      base::Bind(&OnGetStartPageToken, metadata, callback,
+                 base::Owned(start_page_token)));
 }
 
 void FileSystem::MarkCacheFileAsMounted(

components/drive/chromeos/resource_metadata.cc

@@ -235,20 +235,6 @@ void ResourceMetadata::DestroyOnBlockingPool() {
   delete this;
 }
 
-FileError ResourceMetadata::GetLargestChangestamp(int64_t* out_value) {
-  DCHECK(blocking_task_runner_->RunsTasksInCurrentSequence());
-  return storage_->GetLargestChangestamp(out_value);
-}
-
-FileError ResourceMetadata::SetLargestChangestamp(int64_t value) {
-  DCHECK(blocking_task_runner_->RunsTasksInCurrentSequence());
-
-  if (!EnoughDiskSpaceIsAvailableForDBOperation(storage_->directory_path()))
-    return FILE_ERROR_NO_LOCAL_SPACE;
-
-  return storage_->SetLargestChangestamp(value);
-}
-
 FileError ResourceMetadata::GetStartPageToken(std::string* out_value) {
   DCHECK(blocking_task_runner_->RunsTasksInCurrentSequence());
   return storage_->GetStartPageToken(out_value);

components/drive/chromeos/resource_metadata.h

@@ -56,12 +56,6 @@ class ResourceMetadata {
   // Resets this object.
   FileError Reset();
 
-  // Returns the largest changestamp.
-  FileError GetLargestChangestamp(int64_t* out_value);
-
-  // Sets the largest changestamp.
-  FileError SetLargestChangestamp(int64_t value);
-
   // Returns the start page token for the users default corpus.
   FileError GetStartPageToken(std::string* out_value);
 

components/drive/file_system_metadata.cc

@@ -7,10 +7,7 @@
 namespace drive {
 
 FileSystemMetadata::FileSystemMetadata()
-    : largest_changestamp(0),
-      refreshing(false),
-      last_update_check_error(FILE_ERROR_OK) {
-}
+    : refreshing(false), last_update_check_error(FILE_ERROR_OK) {}
 
 FileSystemMetadata::~FileSystemMetadata() {
 }

components/drive/file_system_metadata.h

@@ -6,6 +6,7 @@
 #define COMPONENTS_DRIVE_FILE_SYSTEM_METADATA_H_
 
 #include <stdint.h>
+#include <string>
 
 #include "base/time/time.h"
 #include "components/drive/file_errors.h"
@@ -17,9 +18,9 @@ struct FileSystemMetadata {
   FileSystemMetadata();
   ~FileSystemMetadata();
 
-  // The largest changestamp that the file system holds (may be different
+  // The start_page_token that the file system holds (may be different
   // from the one on the server)
-  int64_t largest_changestamp;
+  std::string start_page_token = "";
 
   // True if the resource metadata is now being fetched from the server.
   bool refreshing;

components/drive/resource_metadata_unittest.cc

@@ -171,16 +171,6 @@ class ResourceMetadataTest : public testing::Test {
       resource_metadata_;
 };
 
-TEST_F(ResourceMetadataTest, LargestChangestamp) {
-  const int64_t kChangestamp = 123456;
-  EXPECT_EQ(FILE_ERROR_OK,
-            resource_metadata_->SetLargestChangestamp(kChangestamp));
-  int64_t changestamp = 0;
-  EXPECT_EQ(FILE_ERROR_OK,
-            resource_metadata_->GetLargestChangestamp(&changestamp));
-  EXPECT_EQ(kChangestamp, changestamp);
-}
-
 TEST_F(ResourceMetadataTest, StartPageToken) {
   constexpr char kStartPageToken[] = "1234567";
   EXPECT_EQ(FILE_ERROR_OK,