From 6dcc6a8a610135d3b630411217b785fcd9a84ef7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9onard=20Beck?= <leonard.beck@gmail.com>
Date: Tue, 11 Jun 2013 17:23:13 +0200
Subject: [PATCH] Bug 654550 - Add a preference to disable media statistics. r
 = padenot,jaws

---
 .../html/content/public/HTMLVideoElement.h    |  3 +
 content/html/content/src/HTMLVideoElement.cpp | 20 ++++++
 content/media/test/Makefile.in                |  1 +
 content/media/test/manifest.js                |  7 ++
 content/media/test/test_bug654550.html        | 70 +++++++++++++++++++
 layout/build/nsLayoutStatics.cpp              |  3 +
 modules/libpref/src/init/all.js               |  3 +
 7 files changed, 107 insertions(+)
 create mode 100644 content/media/test/test_bug654550.html

diff --git a/content/html/content/public/HTMLVideoElement.h b/content/html/content/public/HTMLVideoElement.h
index 62a60c64b05d..944ee7a23f8f 100644
--- a/content/html/content/public/HTMLVideoElement.h
+++ b/content/html/content/public/HTMLVideoElement.h
@@ -47,6 +47,9 @@ public:
                                 const nsAString& aValue,
                                 nsAttrValue& aResult);
   NS_IMETHOD_(bool) IsAttributeMapped(const nsIAtom* aAttribute) const MOZ_OVERRIDE;
+
+  static void Init();
+
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const MOZ_OVERRIDE;
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const MOZ_OVERRIDE;
diff --git a/content/html/content/src/HTMLVideoElement.cpp b/content/html/content/src/HTMLVideoElement.cpp
index d80bfa351346..840dbd78d61b 100644
--- a/content/html/content/src/HTMLVideoElement.cpp
+++ b/content/html/content/src/HTMLVideoElement.cpp
@@ -33,12 +33,15 @@
 #include "nsIPowerManagerService.h"
 #include "MediaError.h"
 #include "MediaDecoder.h"
+#include "mozilla/Preferences.h"
 
 NS_IMPL_NS_NEW_HTML_ELEMENT(Video)
 
 namespace mozilla {
 namespace dom {
 
+static bool sVideoStatsEnabled;
+
 NS_IMPL_ADDREF_INHERITED(HTMLVideoElement, HTMLMediaElement)
 NS_IMPL_RELEASE_INHERITED(HTMLVideoElement, HTMLMediaElement)
 
@@ -160,6 +163,9 @@ NS_IMPL_URI_ATTR(HTMLVideoElement, Poster, poster)
 uint32_t HTMLVideoElement::MozParsedFrames() const
 {
   MOZ_ASSERT(NS_IsMainThread(), "Should be on main thread.");
+  if (!sVideoStatsEnabled) {
+    return 0;
+  }
   return mDecoder ? mDecoder->GetFrameStatistics().GetParsedFrames() : 0;
 }
 
@@ -172,6 +178,9 @@ NS_IMETHODIMP HTMLVideoElement::GetMozParsedFrames(uint32_t *aMozParsedFrames)
 uint32_t HTMLVideoElement::MozDecodedFrames() const
 {
   MOZ_ASSERT(NS_IsMainThread(), "Should be on main thread.");
+  if (!sVideoStatsEnabled) {
+    return 0;
+  }
   return mDecoder ? mDecoder->GetFrameStatistics().GetDecodedFrames() : 0;
 }
 
@@ -184,6 +193,9 @@ NS_IMETHODIMP HTMLVideoElement::GetMozDecodedFrames(uint32_t *aMozDecodedFrames)
 uint32_t HTMLVideoElement::MozPresentedFrames() const
 {
   MOZ_ASSERT(NS_IsMainThread(), "Should be on main thread.");
+  if (!sVideoStatsEnabled) {
+    return 0;
+  }
   return mDecoder ? mDecoder->GetFrameStatistics().GetPresentedFrames() : 0;
 }
 
@@ -196,6 +208,9 @@ NS_IMETHODIMP HTMLVideoElement::GetMozPresentedFrames(uint32_t *aMozPresentedFra
 uint32_t HTMLVideoElement::MozPaintedFrames()
 {
   MOZ_ASSERT(NS_IsMainThread(), "Should be on main thread.");
+  if (!sVideoStatsEnabled) {
+    return 0;
+  }
   layers::ImageContainer* container = GetImageContainer();
   return container ? container->GetPaintCount() : 0;
 }
@@ -282,5 +297,10 @@ HTMLVideoElement::WakeLockUpdate()
   }
 }
 
+void
+HTMLVideoElement::Init()
+{
+  Preferences::AddBoolVarCache(&sVideoStatsEnabled, "media.video_stats.enabled");
+}
 } // namespace dom
 } // namespace mozilla
diff --git a/content/media/test/Makefile.in b/content/media/test/Makefile.in
index 20da0b8b494f..eac71827c09a 100644
--- a/content/media/test/Makefile.in
+++ b/content/media/test/Makefile.in
@@ -72,6 +72,7 @@ MOCHITEST_FILES = \
 		test_bug493187.html \
 		test_bug495145.html \
 		test_bug495300.html \
+		test_bug654550.html \
 		test_bug686942.html \
 		test_can_play_type.html \
 		test_can_play_type_mpeg.html \
diff --git a/content/media/test/manifest.js b/content/media/test/manifest.js
index 28d5f9255c48..8b143e5e40d4 100644
--- a/content/media/test/manifest.js
+++ b/content/media/test/manifest.js
@@ -16,6 +16,13 @@ var gSmallTests = [
   { name:"bogus.duh", type:"bogus/duh" }
 ];
 
+// Used by test_bug654550.html, for videoStats preference
+var gVideoTests = [
+  { name:"320x240.ogv", type:"video/ogg", width:320, height:240, duration:0.266 },
+  { name:"seek.webm", type:"video/webm", width:320, height:240, duration:3.966 },
+  { name:"bogus.duh", type:"bogus/duh" }
+];
+
 // Used by test_progress to ensure we get the correct progress information
 // during resource download.
 var gProgressTests = [
diff --git a/content/media/test/test_bug654550.html b/content/media/test/test_bug654550.html
new file mode 100644
index 000000000000..341ad3051b36
--- /dev/null
+++ b/content/media/test/test_bug654550.html
@@ -0,0 +1,70 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=654550
+-->
+
+<head>
+  <title>Test for Bug 654550</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="text/javascript" src="manifest.js"></script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=654550">Mozilla Bug 654550</a>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+  /* Test for Bug 654550 */
+
+  var manager = new MediaTestManager;
+
+  function checkStats(v, aShouldBeEnabled) {
+    if (aShouldBeEnabled) {
+      ok(v.mozParsedFrames != 0,
+         "At least one value should be different from 0 if stats are enabled");
+    } else {
+      ok(!v.mozParsedFrames,
+        "mozParsedFrames should be 0 if stats are disabled");
+      ok(!v.mozDecodedFrames,
+        "mozDecodedFrames should be 0 if stats are disabled");
+      ok(!v.mozPresentedFrames,
+        "mozPresentedFrames should be 0 if stats are disabled");
+      ok(!v.mozPaintedFrames,
+        "mozPaintedFrames should be 0 if stats are disabled");
+    }
+
+  }
+
+  function ontimeupdate(event) {
+    var v = event.target;
+    if (SpecialPowers.getBoolPref("media.video_stats.enabled")) {
+      checkStats(v, true);
+      SpecialPowers.setBoolPref("media.video_stats.enabled", false);
+    } else {
+      checkStats(v, false);
+      SpecialPowers.setBoolPref("media.video_stats.enabled", true);
+      v.removeEventListener("timeupdate", ontimeupdate);
+      SpecialPowers.clearUserPref("media.video_stats.enabled");
+      manager.finished(v.token);
+    }
+  }
+
+
+  function startTest(test, token) {
+    var v = document.createElement('video');
+    v.token = token;
+    v.src = test.name;
+    manager.started(token);
+    v.play();
+    SpecialPowers.setBoolPref("media.video_stats.enabled", true);
+    v.addEventListener("timeupdate", ontimeupdate);
+    SimpleTest.waitForExplicitFinish();
+  }
+
+  manager.runTests(gVideoTests, startTest);
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/layout/build/nsLayoutStatics.cpp b/layout/build/nsLayoutStatics.cpp
index 5764e5be1384..c5ad9c6e876f 100644
--- a/layout/build/nsLayoutStatics.cpp
+++ b/layout/build/nsLayoutStatics.cpp
@@ -116,6 +116,7 @@ using namespace mozilla::system;
 #include "mozilla/dom/time/DateCacheCleaner.h"
 #include "nsIMEStateManager.h"
 #include "nsDocument.h"
+#include "mozilla/dom/HTMLVideoElement.h"
 
 extern void NS_ShutdownEventTargetChainItemRecyclePool();
 
@@ -272,6 +273,8 @@ nsLayoutStatics::Initialize()
 
   InitializeDateCacheCleaner();
 
+  HTMLVideoElement::Init();
+
   return NS_OK;
 }
 
diff --git a/modules/libpref/src/init/all.js b/modules/libpref/src/init/all.js
index 947e3a79f7b3..079882928a4d 100644
--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -232,6 +232,9 @@ pref("media.autoplay.enabled", true);
 // MediaDecoderReader's mVideoQueue.
 pref("media.video-queue.default-size", 10);
 
+// Whether to disable the video stats to prevent fingerprinting
+pref("media.video_stats.enabled", true);
+
 // Whether to enable the audio writing APIs on the audio element
 pref("media.audio_data.enabled", true);