[CRD iOS] Fix warnings from clang static analyzer

This CL fixes a few warnings reported by the clang static analyzer:
* Remove the unnecessary `next_frame += bytes_to_copy` line from
  AudioPlayerBuffer.
* Call dictionaryWithDictionary with empty dictionary if data is nil.
* Add [super viewDidLoad] calls to view controllers.

Note that none of them causes actual problem in the official app.

Bug: 791222
Change-Id: Icaaf8a43481eb68950dbf6c25c9d7789237aed5e
Reviewed-on: https://chromium-review.googlesource.com/809928
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522216}

remoting/client/audio/audio_player_buffer.cc

@@ -166,7 +166,6 @@ void AudioPlayerBuffer::ProcessFrameRequestQueue() {
 
       memcpy(next_frame, packet_data.data() + bytes_consumed_, bytes_to_copy);
 
-      next_frame += bytes_to_copy;
       bytes_consumed_ += bytes_to_copy;
       activeRequest->bytes_extracted_ += bytes_to_copy;
       queued_bytes_ -= bytes_to_copy;

remoting/ios/app/app_view_controller_chromium.mm

@@ -32,6 +32,8 @@
 }
 
 - (void)viewDidLoad {
+  [super viewDidLoad];
+
   [self addChildViewController:_mainViewController];
   [self.view addSubview:_mainViewController.view];
   [_mainViewController didMoveToParentViewController:self];

remoting/ios/app/first_launch_view_controller.mm

@@ -31,6 +31,8 @@ static const float kButtonHeight = 80.f;
 #pragma mark - UIViewController
 
 - (void)viewDidLoad {
+  [super viewDidLoad];
+
   UIImageView* imageView = [[UIImageView alloc]
       initWithImage:[UIImage imageNamed:@"launchscreen_app_logo"]];
   imageView.translatesAutoresizingMaskIntoConstraints = NO;

remoting/ios/app/host_fetching_error_view_controller.mm

@@ -41,6 +41,8 @@ static const CGFloat kButtonBottomPaddingAdjustment = -5;
 }
 
 - (void)viewDidLoad {
+  [super viewDidLoad];
+
   UIView* contentView = [[UIView alloc] initWithFrame:CGRectZero];
   contentView.backgroundColor = RemotingTheme.setupListBackgroundColor;
   contentView.translatesAutoresizingMaskIntoConstraints = NO;

remoting/ios/app/host_fetching_view_controller.mm

@@ -17,6 +17,8 @@ static const CGFloat kActivityIndicatorRadius = 20.f;
 @implementation HostFetchingViewController
 
 - (void)viewDidLoad {
+  [super viewDidLoad];
+
   MDCActivityIndicator* activityIndicator = [[MDCActivityIndicator alloc] init];
   activityIndicator.translatesAutoresizingMaskIntoConstraints = NO;
   activityIndicator.cycleColors = @[ RemotingTheme.refreshIndicatorColor ];

remoting/ios/keychain_wrapper.mm

@@ -125,13 +125,12 @@ NSString* const kKeychainPairingSecret = @"kKeychainPairingSecret";
   if (mapString &&
       [mapString respondsToSelector:@selector(dataUsingEncoding:)]) {
     NSData* data = [mapString dataUsingEncoding:NSUTF8StringEncoding];
-    NSDictionary* pairingMap;
-    if (data) {
-      pairingMap = (NSDictionary*)[NSJSONSerialization
-          JSONObjectWithData:data
-                     options:NSJSONReadingMutableContainers
-                       error:&err];
-    }
+    NSDictionary* pairingMap =
+        data ? (NSDictionary*)[NSJSONSerialization
+                   JSONObjectWithData:data
+                              options:NSJSONReadingMutableContainers
+                                error:&err]
+             : @{};
     if (!err) {
       return [NSMutableDictionary dictionaryWithDictionary:pairingMap];
     }