alternate ntp: implement Show/HideBars SearchBox API to reduce jank when showing/hiding bars

this is the chrome side combining melevin@'s renderer parts with my browser parts; gws side is implemented by melevin@.

- when suggestions show/hide, bookmark and info bars hide/show respectively; this causes contents to shift up/down respectively, resulting in jank.
- to reduce jank, these APIs synchronize the showing/hiding of suggestions in gws with the showing/hiding of bookmark and info bars in browser.
- gws sends HideBars() whenever suggestions show, and ShowBars() whenever they close.
- browser only obliges when bookmark and/or info bars are enabled and only on NTP and SERP pages, but always fires onbarshidden event for every HideBars() call, so that gws can proceed to show suggestions.

BUG=176146,178550,175776
TEST=verify as per bug rpts


Review URL: https://chromiumcodereview.appspot.com/12631008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@188994 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 9 insertions, 3 deletions

diff --git a/chrome/browser/ui/browser_instant_controller.cc b/chrome/browser/ui/browser_instant_controller.cc
index ca47c0f..068aa504 100644
--- a/chrome/browser/ui/browser_instant_controller.cc
+++ b/chrome/browser/ui/browser_instant_controller.cc
@@ -236,8 +236,14 @@ void BrowserInstantController::ResetInstant(const std::string& pref_name) {
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserInstantController, search::SearchModelObserver implementation:
 
-void BrowserInstantController::ModeChanged(const search::Mode& old_mode,
-                                           const search::Mode& new_mode) {
+void BrowserInstantController::ModelChanged(
+    const search::SearchModel::State& old_state,
+    const search::SearchModel::State& new_state) {
+  if (old_state.mode == new_state.mode)
+    return;
+
+  const search::Mode& new_mode = new_state.mode;
+
   if (search::IsInstantExtendedAPIEnabled()) {
     // Record some actions corresponding to the mode change. Note that to get
     // the full story, it's necessary to look at other UMA actions as well,
@@ -252,7 +258,7 @@ void BrowserInstantController::ModeChanged(const search::Mode& old_mode,
   if (new_mode.is_ntp())
     UpdateThemeInfo();
 
-  instant_.SearchModeChanged(old_mode, new_mode);
+  instant_.SearchModeChanged(old_state.mode, new_mode);
 }
 
 ////////////////////////////////////////////////////////////////////////////////