Fixed the audio backgrounding bug

chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc

Index: chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
diff --git a/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc b/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
index 24c58ef9a6acd950d566e73f5f62e0f5225ad8ed..43d6d93381f00b106992fd159fb3226a2d123576 100644
--- a/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
+++ b/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
@@ -3,7 +3,9 @@
 // found in the LICENSE file.
 
 #include "base/command_line.h"
+#include "base/path_service.h"
 #include "base/process/process.h"
+#include "base/test/test_timeouts.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/devtools/devtools_window.h"
 #include "chrome/browser/search/search.h"
@@ -23,6 +25,8 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/test/browser_test_utils.h"
+#include "net/base/filename_util.h"
+#include "net/test/embedded_test_server/embedded_test_server.h"
 
 using content::RenderViewHost;
 using content::RenderWidgetHost;
@@ -531,3 +535,165 @@ IN_PROC_BROWSER_TEST_F(ChromeRenderProcessHostTest,
 
   observer.Wait();
 }
+
+// Sets up the browser in order to start the tests with two tabs open: one
+// called "no audio" in foreground and another called "audio" in background with
+// audio in playing state. Also sets up the variables containing the process
+// associated with each tab, the urls of the two pages and the WebContents of
+// the "audio" page.
+class ChromeRenderProcessHostBackgroundingTest
+    : public ChromeRenderProcessHostTest {
+ public:
+  ChromeRenderProcessHostBackgroundingTest() {}
+
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    command_line->AppendSwitch(switches::kProcessPerTab);
+  }
+
+  void SetUpOnMainThread() override {
+    ASSERT_TRUE(embedded_test_server()->InitializeAndWaitUntilReady());
+
+    // Set up the server and get the test pages.
+    base::FilePath test_data_dir;
+    ASSERT_TRUE(PathService::Get(base::DIR_SOURCE_ROOT, &test_data_dir));
+    embedded_test_server()->ServeFilesFromDirectory(
+        test_data_dir.AppendASCII("chrome/test/data/"));
+    audio_url_ = embedded_test_server()->GetURL("/extensions/loop_audio.html");
+    no_audio_url_ = embedded_test_server()->GetURL("/title1.html");
+
+    // Open a browser, navigate to the audio page and get its WebContents.
+    ui_test_utils::NavigateToURL(browser(), audio_url_);
+    audio_tab_web_contents_ =
+        browser()->tab_strip_model()->GetActiveWebContents();
+
+    // Create a new tab for the no audio page and get the processes
+    // corresponding to each page.

[gab, 2015/08/24 20:59:22]

// Create a new tab for the no audio page and confirm that the processes of each
tabs are different and both valid.

(and remove empty line between this block and ASSERTs as they really belong
together now)

[sebsg, 2015/08/25 01:35:59]

Done.

+    base::Process no_audio_process_ = ShowSingletonTab(no_audio_url_);

[gab, 2015/08/24 20:59:22]

|no_audio_process| (no longer a member variable, same for |audio_process|)

[sebsg, 2015/08/25 01:35:59]

Done.

+    no_audio_tab_web_contents_ =

[gab, 2015/08/24 20:59:22]

Perhaps move this after the ASSERTs as it's now no longer related to this block
so much?

[sebsg, 2015/08/25 01:35:59]

Done.

+        browser()->tab_strip_model()->GetActiveWebContents();
+    base::Process audio_process_ = ProcessFromHandle(
+        audio_tab_web_contents_->GetRenderProcessHost()->GetHandle());
+
+    ASSERT_TRUE(no_audio_process_.IsValid());
+    ASSERT_TRUE(audio_process_.IsValid());
+    ASSERT_NE(audio_process_.Pid(), no_audio_process_.Pid());
+  }
+
+ protected:
+  bool IsProcessBackgroundedHelper(const content::WebContents& web_contents) {

[gab, 2015/08/24 20:59:22]

I'd say const* is arguably better here so that you don't have to deref
everywhere below?

Perhaps with
DCHECK(web_contents);
to enforce the contract that this method doesn't handle null ptrs (in fact
pretty sure WebContents tends to be passed by pointer most of the time -- looks
like 93 for const* vs 2 for const&:
https://code.google.com/p/chromium/codesearch#search/&q=const%5C%20content::W...)

[sebsg, 2015/08/25 01:35:59]

Done.

+#if defined(OS_MACOSX)
+    content::RenderProcessHost* rph = web_contents.GetRenderProcessHost();

[gab, 2015/08/24 20:59:22]

const

[sebsg, 2015/08/25 01:35:59]

Done.

+    base::Process process = ProcessFromHandle(rph->GetHandle());

[gab, 2015/08/24 20:59:22]

const

[sebsg, 2015/08/25 01:35:59]

Done.

+    return process.IsProcessBackgrounded(rph->GetMachTaskPortForTesting());
+#else
+    base::Process process =

[gab, 2015/08/24 20:59:22]

const

[sebsg, 2015/08/25 01:35:59]

Done.

+        ProcessFromHandle(web_contents.GetRenderProcessHost()->GetHandle());
+    return process.IsProcessBackgrounded();
+#endif  // defined(OS_MACOSX)
+  }
+
+  GURL audio_url_;
+  GURL no_audio_url_;
+
+  content::WebContents* audio_tab_web_contents_;
+  content::WebContents* no_audio_tab_web_contents_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ChromeRenderProcessHostBackgroundingTest);
+};
+
+// Test to make sure that a process is backgrounded when the audio stops playing
+// from the active tab and there is an immediate tab switch.
+IN_PROC_BROWSER_TEST_F(ChromeRenderProcessHostBackgroundingTest,
+                       ProcessPriorityAfterStoppedAudio) {
+  // This test is invalid on platforms that can't background.
+  if (!base::Process::CanBackgroundProcesses())
+    return;
+
+  ShowSingletonTab(audio_url_);
+
+  // Wait until the no audio page is backgrounded and the audio page is not
+  // backgrounded.
+  while (!IsProcessBackgroundedHelper(*no_audio_tab_web_contents_) ||
+         IsProcessBackgroundedHelper(*audio_tab_web_contents_)) {
+    base::RunLoop().RunUntilIdle();
+    base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  }
+
+  // Pause the audio and immediately switch to the no audio tab.
+  ASSERT_TRUE(content::ExecuteScript(
+      audio_tab_web_contents_,
+      "document.getElementById('audioPlayer').pause();"));
+  ShowSingletonTab(no_audio_url_);
+
+  // Wait until the no audio page is not backgrounded and the audio page is
+  // backgrounded.
+  while (IsProcessBackgroundedHelper(*no_audio_tab_web_contents_) ||
+         !IsProcessBackgroundedHelper(*audio_tab_web_contents_)) {
+    base::RunLoop().RunUntilIdle();
+    base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  }
+}
+
+// Test to make sure that a process is backgrounded automatically when audio
+// stops playing from a hidden tab.
+IN_PROC_BROWSER_TEST_F(ChromeRenderProcessHostBackgroundingTest,
+                       ProcessPriorityAfterAudioStopsOnNotVisibleTab) {
+  // This test is invalid on platforms that can't background.
+  if (!base::Process::CanBackgroundProcesses())
+    return;
+
+  // Wait until the two pages are not backgrounded.
+  while (IsProcessBackgroundedHelper(*no_audio_tab_web_contents_) ||
+         IsProcessBackgroundedHelper(*audio_tab_web_contents_)) {
+    base::RunLoop().RunUntilIdle();
+    base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  }
+
+  // Stop the audio.
+  ASSERT_TRUE(content::ExecuteScript(
+      audio_tab_web_contents_,
+      "document.getElementById('audioPlayer').pause();"));
+
+  // Wait until the no audio page is not backgrounded and the audio page is
+  // backgrounded.
+  while (IsProcessBackgroundedHelper(*no_audio_tab_web_contents_) ||
+         !IsProcessBackgroundedHelper(*audio_tab_web_contents_)) {
+    base::RunLoop().RunUntilIdle();
+    base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  }
+}
+
+// Test to make sure that a process is un-backgrounded automatically when audio
+// starts playing from a backgrounded tab.
+IN_PROC_BROWSER_TEST_F(ChromeRenderProcessHostBackgroundingTest,
+                       ProcessPriorityAfterAudioStartsFromBackgroundTab) {
+  // This test is invalid on platforms that can't background.
+  if (!base::Process::CanBackgroundProcesses())
+    return;
+
+  // Stop the audio.
+  ASSERT_TRUE(content::ExecuteScript(
+      audio_tab_web_contents_,
+      "document.getElementById('audioPlayer').pause();"));
+
+  // Wait until the no audio page is not backgrounded and the audio page is
+  // backgrounded.
+  while (IsProcessBackgroundedHelper(*no_audio_tab_web_contents_) ||
+         !IsProcessBackgroundedHelper(*audio_tab_web_contents_)) {
+    base::RunLoop().RunUntilIdle();
+    base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  }
+
+  // Start the audio from the backgrounded tab.
+  ASSERT_TRUE(
+      content::ExecuteScript(audio_tab_web_contents_,
+                             "document.getElementById('audioPlayer').play();"));
+
+  // Wait until the two pages are not backgrounded.
+  while (IsProcessBackgroundedHelper(*no_audio_tab_web_contents_) ||
+         IsProcessBackgroundedHelper(*audio_tab_web_contents_)) {
+    base::RunLoop().RunUntilIdle();
+    base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  }
+}