Bug 1177018 - Only enable APZ test logging for tests that actually use it. r=kats

This avoids excessive amounts of test data accumulating which can slow tests down.

As part of this change, the pref for enabling the logging was made 'Live'.

--HG--
extra : rebase_source : e1d0547e5d3125e9db44bb47ddfff3b4f8d50e99
extra : source : 73fb13743a74a5a920d099fda70d9b1a1fa3a6ed

gfx/layers/apz/test/test_bug1151663.html

@@ -17,7 +17,9 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1151663
     // inside an iframe which means we have no control over the root APZC.
     var w = null;
     window.onload = function() {
-      w = window.open("helper_bug1151663.html", "_blank");
+      SpecialPowers.pushPrefEnv({"set": [["apz.test.logging_enabled", true]]}, function() {
+        w = window.open("helper_bug1151663.html", "_blank");
+      });
     };
 
     function finishTest() {

gfx/layers/apz/test/test_bug982141.html

@@ -17,7 +17,9 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=982141
     // inside an iframe which means we have no control over the root APZC.
     var w = null;
     window.onload = function() {
-      w = window.open("helper_bug982141.html", "_blank");
+      SpecialPowers.pushPrefEnv({"set": [["apz.test.logging_enabled", true]]}, function() {
+        w = window.open("helper_bug982141.html", "_blank");
+      });
     };
 
     function finishTest() {

gfx/layers/apz/test/test_layerization.html

@@ -154,7 +154,10 @@ SimpleTest.waitForExplicitFinish();
 // Disable smooth scrolling, because it results in long-running scroll
 // animations that can result in a 'scroll' event triggered by an earlier
 // wheel event as corresponding to a later wheel event.
-SpecialPowers.pushPrefEnv({"set": [["general.smoothScroll", false]]},
+// Also enable APZ test logging, since we use that data to determine whether
+// a scroll frame was layerized.
+SpecialPowers.pushPrefEnv({"set": [["general.smoothScroll", false],
+                                   ["apz.test.logging_enabled", true]]},
                           function() {
                             SimpleTest.waitForFocus(startTest, window);
                           });

gfx/layers/client/ClientLayerManager.cpp

@@ -231,9 +231,14 @@ ClientLayerManager::BeginTransactionWithTarget(gfxContext* aTarget)
   }
 
   // If this is a new paint, increment the paint sequence number.
-  if (!mIsRepeatTransaction && gfxPrefs::APZTestLoggingEnabled()) {
+  if (!mIsRepeatTransaction) {
+    // Increment the paint sequence number even if test logging isn't
+    // enabled in this process; it may be enabled in the parent process,
+    // and the parent process expects unique sequence numbers.
     ++mPaintSequenceNumber;
-    mApzTestData.StartNewPaint(mPaintSequenceNumber);
+    if (gfxPrefs::APZTestLoggingEnabled()) {
+      mApzTestData.StartNewPaint(mPaintSequenceNumber);
+    }
   }
 }
 

gfx/thebes/gfxPrefs.h

@@ -176,7 +176,7 @@ private:
   DECL_GFX_PREF(Live, "apz.pan_repaint_interval",              APZPanRepaintInterval, int32_t, 250);
   DECL_GFX_PREF(Live, "apz.printtree",                         APZPrintTree, bool, false);
   DECL_GFX_PREF(Live, "apz.smooth_scroll_repaint_interval",    APZSmoothScrollRepaintInterval, int32_t, 75);
-  DECL_GFX_PREF(Once, "apz.test.logging_enabled",              APZTestLoggingEnabled, bool, false);
+  DECL_GFX_PREF(Live, "apz.test.logging_enabled",              APZTestLoggingEnabled, bool, false);
   DECL_GFX_PREF(Live, "apz.touch_start_tolerance",             APZTouchStartTolerance, float, 1.0f/4.5f);
   DECL_GFX_PREF(Live, "apz.use_paint_duration",                APZUsePaintDuration, bool, true);
   DECL_GFX_PREF(Live, "apz.velocity_bias",                     APZVelocityBias, float, 1.0f);

testing/profiles/prefs_general.js

@@ -252,9 +252,6 @@ user_pref("identity.fxaccounts.remote.signin.uri", "https://%(server)s/fxa-signi
 user_pref("identity.fxaccounts.settings.uri", "https://%(server)s/fxa-settings");
 user_pref('identity.fxaccounts.remote.webchannel.uri', 'https://%(server)s/');
 
-// Enable logging of APZ test data (see bug 961289).
-user_pref('apz.test.logging_enabled', true);
-
 // Make sure SSL Error reports don't hit the network
 user_pref("security.ssl.errorReporting.url", "https://example.com/browser/browser/base/content/test/general/pinning_reports.sjs?succeed");