Expands the chrome.experimental.processes extension API.

Adds an onUpdated event that reports process metrics from the TaskManager,
and modifies the TaskManager to support multiple independent observers.

BUG=32302
TEST=ExtensionApiTest.Processes browsertest
TEST=process_monitor sample extension

Review URL: http://codereview.chromium.org/3597016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@62458 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 0 deletions

diff --git a/chrome/browser/extensions/extension_message_service.cc b/chrome/browser/extensions/extension_message_service.cc
index 7e675f5..a25b384 100644
--- a/chrome/browser/extensions/extension_message_service.cc
+++ b/chrome/browser/extensions/extension_message_service.cc
@@ -10,6 +10,8 @@
 #include "base/values.h"
 #include "chrome/browser/child_process_security_policy.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
+#include "chrome/browser/extensions/extension_processes_api.h"
+#include "chrome/browser/extensions/extension_processes_api_constants.h"
 #include "chrome/browser/extensions/extension_tabs_module.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
@@ -168,10 +170,22 @@ void ExtensionMessageService::AddEventListener(const std::string& event_name,
     extension_devtools_manager_->AddEventListener(event_name,
                                                   render_process_id);
   }
+
+  // We lazily tell the TaskManager to start updating when listeners to the
+  // processes.onUpdated event arrive.
+  if (event_name.compare(extension_processes_api_constants::kOnUpdated) == 0) {
+    ExtensionProcessesEventRouter::GetInstance()->ListenerAdded();
+  }
 }
 
 void ExtensionMessageService::RemoveEventListener(const std::string& event_name,
                                                   int render_process_id) {
+  // If a processes.onUpdated event listener is removed (or a process with one
+  // exits), then we let the TaskManager know that it has one fewer listener.
+  if (event_name.compare(extension_processes_api_constants::kOnUpdated) == 0) {
+    ExtensionProcessesEventRouter::GetInstance()->ListenerRemoved();
+  }
+
   DCHECK_EQ(listeners_[event_name].count(render_process_id), 1u)
       << " PID=" << render_process_id << " event=" << event_name;
   listeners_[event_name].erase(render_process_id);