Bug 1277359 - Add chrome-only navigator.cpuHasSSE2 api. r=smaug

Make the host's support for SSE2 instructions available to
javascript so we can report that status in update pings.

MozReview-Commit-ID: FhWPjLxKRZy

--HG--
extra : rebase_source : f804896705090fbc268a41db8edf755d72c643aa

dom/base/Navigator.cpp

@@ -768,6 +768,12 @@ Navigator::HardwareConcurrency()
   return rts->ClampedHardwareConcurrency();
 }
 
+bool
+Navigator::CpuHasSSE2()
+{
+  return mozilla::supports_sse2();
+}
+
 void
 Navigator::RefreshMIMEArray()
 {

dom/base/Navigator.h

@@ -198,6 +198,7 @@ public:
   PowerManager* GetMozPower(ErrorResult& aRv);
   bool JavaEnabled(ErrorResult& aRv);
   uint64_t HardwareConcurrency();
+  bool CpuHasSSE2();
   bool TaintEnabled()
   {
     return false;

dom/webidl/Navigator.webidl

@@ -234,6 +234,12 @@ partial interface Navigator {
    */
   [Throws, Pref="dom.wakelock.enabled", Func="Navigator::HasWakeLockSupport", UnsafeInPrerendering]
   MozWakeLock requestWakeLock(DOMString aTopic);
+
+  /**
+   * Make CPU instruction subset information available for UpdateUtils.
+   */
+  [ChromeOnly]
+  readonly attribute boolean cpuHasSSE2;
 };
 
 partial interface Navigator {
@@ -403,3 +409,6 @@ partial interface Navigator {
 interface NavigatorConcurrentHardware {
   readonly attribute unsigned long long hardwareConcurrency;
 };
+
+partial interface Navigator {
+};