Merge pull request #696 in MOBILE-SDK/app_mobile-sdk-ios from github_…

…sync_blank_ads to master

* commit '9343f6fb457ccd8e54f4d3a7c872565463dfe3af':
  Fix data race where ads load blank occasionally (#61)

sdk/sourcefiles/internal/ANAdWebViewController.m

@@ -53,6 +53,7 @@ @interface ANAdWebViewController () <WKNavigationDelegate, WKUIDelegate, WKScrip
 @property (nonatomic, readwrite, strong)    ANWebView      *webView;
 @property (nonatomic, readwrite, assign)  BOOL  isMRAID;
 @property (nonatomic, readwrite, assign)  BOOL  completedFirstLoad;
+@property (nonatomic, readwrite, strong)  WKNavigation *firstNavigation;
 
 @property (nonatomic, readwrite, strong)                        NSTimer     *viewabilityTimer;
 @property (nonatomic, readwrite, assign, getter=isViewable)     BOOL         viewable;
@@ -170,7 +171,7 @@ - (instancetype)initWithSize:(CGSize)size
             if (!strongSelf)  {
                 return;
             }
-            [strongSelf.webView loadHTMLString:htmlToLoad baseURL:base];
+            strongSelf.firstNavigation = [strongSelf.webView loadHTMLString:htmlToLoad baseURL:base];
         });
     });
 
@@ -314,7 +315,9 @@ -(void) webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation
 
 - (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
 {
-    [self processWebViewDidFinishLoad];
+    if (navigation == self.firstNavigation) {
+        [self processWebViewDidFinishLoad];
+    }
 }
 
 - (void)webView:(WKWebView *)webView didFailNavigation:(WKNavigation *)navigation withError:(NSError *)error {
@@ -526,6 +529,7 @@ - (void)processWebViewDidFinishLoad
     if (!self.completedFirstLoad)
     {
         self.completedFirstLoad = YES;
+        self.firstNavigation = nil;
         // If it is VAST ad then donot call didCompleteFirstLoadFromWebViewController videoAdReady will call it later.
         if ([self.videoXML length] > 0)
         {