[ReactNative] Optimize console.profile and add markers on JS entry points

Summary:
@public

Right now the profiler shows how long the executor took on JS but doesn't show
how long each of the batched calls took, this adds a *very* high level view of JS
execution (still doesn't show properly calls dispatched with setImmediate)

Also added a global property on JS to avoid trips to Native when profiling is
disabled.

Test Plan:
Run the Profiler on any app

{F22491690}

React/Base/RCTProfile.h

@@ -20,6 +20,9 @@
  * before before using it.
  */
 
+NSString *const RCTProfileDidStartProfiling;
+NSString *const RCTProfileDidEndProfiling;
+
 #if RCT_DEV
 
 #define RCTProfileBeginFlowEvent() \

React/Base/RCTProfile.m

@@ -17,6 +17,9 @@
 #import "RCTDefines.h"
 #import "RCTUtils.h"
 
+NSString *const RCTProfileDidStartProfiling = @"RCTProfileDidStartProfiling";
+NSString *const RCTProfileDidEndProfiling = @"RCTProfileDidEndProfiling";
+
 #if RCT_DEV
 
 #pragma mark - Prototypes
@@ -113,10 +116,16 @@ void RCTProfileInit(void)
       RCTProfileSamples: [[NSMutableArray alloc] init],
     };
   );
+
+  [[NSNotificationCenter defaultCenter] postNotificationName:RCTProfileDidStartProfiling
+                                                      object:nil];
 }
 
 NSString *RCTProfileEnd(void)
 {
+  [[NSNotificationCenter defaultCenter] postNotificationName:RCTProfileDidEndProfiling
+                                                      object:nil];
+
   RCTProfileLock(
     NSString *log = RCTJSONStringify(RCTProfileInfo, NULL);
     RCTProfileEventID = 0;

React/Executors/RCTContextExecutor.m

@@ -133,22 +133,27 @@ static JSValueRef RCTConsoleProfile(JSContextRef context, JSObjectRef object, JS
     profileName = [NSString stringWithFormat:@"Profile %d", profileCounter++];
   }
 
-  [profiles addObjectsFromArray:@[profileName, profileID]];
+  id profileInfo = [NSNull null];
+  if (argumentCount > 1 && !JSValueIsUndefined(context, arguments[1])) {
+    profileInfo = @[RCTJSValueToNSString(context, arguments[1])];
+  }
+
+  [profiles addObjectsFromArray:@[profileName, profileID, profileInfo]];
 
-  RCTLog(@"Profile '%@' finished.", profileName);
   return JSValueMakeUndefined(context);
 }
 
 static JSValueRef RCTConsoleProfileEnd(JSContextRef context, JSObjectRef object, JSObjectRef thisObject, size_t argumentCount, const JSValueRef arguments[], JSValueRef *exception)
 {
+  NSString *profileInfo = [profiles lastObject];
+  [profiles removeLastObject];
   NSNumber *profileID = [profiles lastObject];
   [profiles removeLastObject];
   NSString *profileName = [profiles lastObject];
   [profiles removeLastObject];
 
-  _RCTProfileEndEvent(profileID, profileName, @"console", nil);
+  _RCTProfileEndEvent(profileID, profileName, @"console", profileInfo);
 
-  RCTLog(@"Profile '%@' started.", profileName);
   return JSValueMakeUndefined(context);
 }
 
@@ -244,6 +249,13 @@ static NSError *RCTNSErrorFromJSError(JSContextRef context, JSValueRef jsError)
 #if RCT_DEV
       [strongSelf _addNativeHook:RCTConsoleProfile withName:"consoleProfile"];
       [strongSelf _addNativeHook:RCTConsoleProfileEnd withName:"consoleProfileEnd"];
+
+      for (NSString *event in @[RCTProfileDidStartProfiling, RCTProfileDidEndProfiling]) {
+        [[NSNotificationCenter defaultCenter] addObserver:self
+                                                 selector:@selector(toggleProfilingFlag:)
+                                                     name:event
+                                                   object:nil];
+      }
 #endif
 
     }];
@@ -252,6 +264,21 @@ static NSError *RCTNSErrorFromJSError(JSContextRef context, JSValueRef jsError)
   return self;
 }
 
+- (void)toggleProfilingFlag:(NSNotification *)notification
+{
+  JSObjectRef globalObject = JSContextGetGlobalObject(_context.ctx);
+
+  bool enabled = [notification.name isEqualToString:RCTProfileDidStartProfiling];
+  JSStringRef JSName = JSStringCreateWithUTF8CString("__BridgeProfilingIsProfiling");
+  JSObjectSetProperty(_context.ctx,
+                      globalObject,
+                      JSName,
+                      JSValueMakeBoolean(_context.ctx, enabled),
+                      kJSPropertyAttributeNone,
+                      NULL);
+  JSStringRelease(JSName);
+}
+
 - (void)_addNativeHook:(JSObjectCallAsFunctionCallback)hook withName:(const char *)name
 {
   JSObjectRef globalObject = JSContextGetGlobalObject(_context.ctx);
@@ -269,6 +296,10 @@ static NSError *RCTNSErrorFromJSError(JSContextRef context, JSValueRef jsError)
 
 - (void)invalidate
 {
+#if RCT_DEV
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+#endif
+
   [_context performSelector:@selector(invalidate) onThread:_javaScriptThread withObject:nil waitUntilDone:NO];
 }
 

React/Modules/RCTUIManager.m

@@ -921,6 +921,7 @@ RCT_EXPORT_METHOD(findSubviewIn:(NSNumber *)reactTag atPoint:(CGPoint)point call
 
 - (void)batchDidComplete
 {
+  RCTProfileBeginEvent();
   // Gather blocks to be executed now that all view hierarchy manipulations have
   // been completed (note that these may still take place before layout has finished)
   for (RCTViewManager *manager in _viewManagers.allValues) {
@@ -951,6 +952,9 @@ RCT_EXPORT_METHOD(findSubviewIn:(NSNumber *)reactTag atPoint:(CGPoint)point call
     _nextLayoutAnimation = nil;
   }
 
+  RCTProfileEndEvent(@"[RCTUIManager batchDidComplete]", @"uimanager", @{
+    @"view_count": @([_viewRegistry count]),
+  });
   [self flushUIBlocks];
 }