Add a new field "source" in launchData of chrome.app.runtime.onLaunched() to trace launch source.

chrome/browser/ui/extensions/application_launch.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/extensions/application_launch.h"
 
 #include <string>
 
 #include "apps/launcher.h"
 #include "base/command_line.h"
+#include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
 #include "chrome/browser/apps/per_app_settings_service.h"
 #include "chrome/browser/apps/per_app_settings_service_factory.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/launch_util.h"
 #include "chrome/browser/extensions/tab_helper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/app_list/app_list_service.h"
@@ skipping 274 matching lines @@
 
   UMA_HISTOGRAM_ENUMERATION(
       "Extensions.AppLaunchContainer", params.container, 100);
 
   if (CanLaunchViaEvent(extension)) {
     // Remember what desktop the launch happened on so that when the app opens a
     // window we can open them on the right desktop.
     PerAppSettingsServiceFactory::GetForBrowserContext(profile)->
         SetDesktopLastLaunchedFrom(extension->id(), params.desktop_type);
 
-    apps::LaunchPlatformAppWithCommandLine(
-        profile, extension, params.command_line, params.current_directory);
+    VLOG(2) << "Launch source: " << params.source;

[benwells, 2014/10/28 21:22:47]

Please remove before landing.

[cylee1, 2014/10/29 16:39:59]

Done.

+
+    apps::LaunchPlatformAppWithCommandLine(profile,
+                                           extension,
+                                           params.command_line,
+                                           params.current_directory,
+                                           params.source);
     return NULL;
   }
 
   // Record v1 app launch. Platform app launch is recorded when dispatching
   // the onLaunched event.
   prefs->SetLastLaunchTime(extension->id(), base::Time::Now());
 
   switch (params.container) {
     case extensions::LAUNCH_CONTAINER_NONE: {
       NOTREACHED();
@@ skipping 20 matching lines @@
                                  const extensions::Extension* extension,
                                  extensions::LaunchContainer container,
                                  WindowOpenDisposition disposition)
     : profile(profile),
       extension_id(extension ? extension->id() : std::string()),
       container(container),
       disposition(disposition),
       desktop_type(chrome::GetActiveDesktop()),
       override_url(),
       override_bounds(),
-      command_line(CommandLine::NO_PROGRAM) {}
+      command_line(CommandLine::NO_PROGRAM),
+      source(extensions::SOURCE_UNKNOWN) {

[benwells, 2014/10/28 21:22:47]

Do you have any idea how many instances of launching this will cause to be
unknown? That is, did you try making this a required parameter to the Params
constructor and see how many call sites you'd have to update?

[cylee1, 2014/10/29 16:39:59]

I've checked all calls to OpenApplication
(https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ui/...)
before start implementing. There're 36 occurrences in total for now (including
from test).

To be honest  I think it's more practical to make "source' an optional
parameters - starts from big entries and add minor entries in an on-demand
manner. For one, there are app-specific sources (e.g., calls from
wallpaper_manager_util.cc and first_run.cc, where only wallpaper app and first
run app will ever care about the source.) For the other, the calls to to
OpenApplication is likely to grow in the future so hard to keep track of every
entry points.

[benwells, 2014/10/30 06:04:28]

I am OK with starting like this, but I think you've missed some important call
sites. Before releasing this I'd like this parameter to be mandatory. It might
mean changing UNKNOWN to UNTRACED or something.

[cylee1, 2014/10/30 13:03:43]

In my proposal document I've listed a bunch of sources I can identify from
sources:
https://docs.google.com/a/chromium.org/document/d/1ozJ7ojy9bblBzivtBaGcNjTJJk...
So far I've implemented those "first tier" ones. Since I'm not very familiar
with the whole chrome apps code base, could tell me if you remember which
important sources I'm missing? 
If possible, I'd like to only include those most important sources in this CL,
and make up other sources in following CLs. Since this CL is getting larger I
feel it's getting hard to manage all changes in one CL. This feature is
protected by a flag so it should be safe.
Changed UNKNOWN to UNTRACKED

[cylee1, 2014/10/31 06:37:53]

I got what you mean, but I think it's fine to change UNKNOWN to UNTRACKED now if
I need to do it sooner or later.
Plus I also considered to use untracked instead of unknown earlier.

+}
 
 AppLaunchParams::AppLaunchParams(Profile* profile,
                                  const extensions::Extension* extension,
                                  WindowOpenDisposition disposition)
     : profile(profile),
       extension_id(extension ? extension->id() : std::string()),
       container(extensions::LAUNCH_CONTAINER_NONE),
       disposition(disposition),
       desktop_type(chrome::GetActiveDesktop()),
       override_url(),
       override_bounds(),
-      command_line(CommandLine::NO_PROGRAM) {
+      command_line(CommandLine::NO_PROGRAM),
+      source(extensions::SOURCE_UNKNOWN) {
   // Look up the app preference to find out the right launch container. Default
   // is to launch as a regular tab.
   container =
       extensions::GetLaunchContainer(ExtensionPrefs::Get(profile), extension);
 }
 
 AppLaunchParams::AppLaunchParams(Profile* profile,
                                  const extensions::Extension* extension,
                                  int event_flags,
                                  chrome::HostDesktopType desktop_type)
     : profile(profile),
       extension_id(extension ? extension->id() : std::string()),
       container(extensions::LAUNCH_CONTAINER_NONE),
       disposition(ui::DispositionFromEventFlags(event_flags)),
       desktop_type(desktop_type),
       override_url(),
       override_bounds(),
-      command_line(CommandLine::NO_PROGRAM) {
+      command_line(CommandLine::NO_PROGRAM),
+      source(extensions::SOURCE_UNKNOWN) {
   if (disposition == NEW_FOREGROUND_TAB || disposition == NEW_BACKGROUND_TAB) {
     container = extensions::LAUNCH_CONTAINER_TAB;
   } else if (disposition == NEW_WINDOW) {
     container = extensions::LAUNCH_CONTAINER_WINDOW;
   } else {
     // Look at preference to find the right launch container.  If no preference
     // is set, launch as a regular tab.
     container =
         extensions::GetLaunchContainer(ExtensionPrefs::Get(profile), extension);
     disposition = NEW_FOREGROUND_TAB;
@@ skipping 68 matching lines @@
 
   // For extensions lacking launch urls, determine a reasonable fallback.
   if (!url.is_valid()) {
     url = extensions::OptionsPageInfo::GetOptionsPage(extension);
     if (!url.is_valid())
       url = GURL(chrome::kChromeUIExtensionsURL);
   }
 
   return url;
 }