Add back dropshadow to IAMs

This was removed when supporting transparent background IAMs, but it makes banner IAMs with white backgrounds look incorrect.

control the IAM dropshadow with a plist setting

iOS_SDK/OneSignalSDK/OneSignalCore/Source/OneSignalCommonDefines.h

@@ -140,6 +140,7 @@
 // Info.plist key
 #define FALLBACK_TO_SETTINGS_MESSAGE @"Onesignal_settings_fallback_message"
 #define ONESIGNAL_SUPRESS_LAUNCH_URLS @"OneSignal_suppress_launch_urls"
+#define ONESIGNAL_IN_APP_HIDE_DROP_SHADOW @"OneSignal_in_app_message_hide_drop_shadow"
 
 // GDPR Privacy Consent
 #define GDPR_CONSENT_GRANTED @"GDPR_CONSENT_GRANTED"

iOS_SDK/OneSignalSDK/OneSignalInAppMessages/UI/OSInAppMessageViewController.m

@@ -195,6 +195,19 @@ - (void)setupInitialMessageUI {
     }];
 }
 
+- (void)updateDropShadow {
+    // the plist value specifies whether the user wants to add drop shadow to the In App Message
+    NSDictionary *bundleDict = [[NSBundle mainBundle] infoDictionary];
+    BOOL hideDropShadow = [bundleDict[ONESIGNAL_IN_APP_HIDE_DROP_SHADOW] boolValue];
+    if (hideDropShadow) {
+        return;
+    }
+    self.messageView.layer.shadowOffset = CGSizeMake(0, 3);
+    self.messageView.layer.shadowColor = [[UIColor blackColor] CGColor];
+    self.messageView.layer.shadowRadius = 3.0f;
+    self.messageView.layer.shadowOpacity = 0.55f;
+}
+
 - (void)displayMessage {
     [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"Displaying In-App Message"];
 
@@ -233,9 +246,11 @@ - (OSResultSuccessBlock)messageContentOnSuccess {
             if (self.waitForTags) {
                 return;
             }
+            [self updateDropShadow];
             [self.delegate messageWillDisplay:self.message];
             [self.messageView loadedHtmlContent:self.pendingHTMLContent withBaseURL:baseUrl];
             self.pendingHTMLContent = nil;
+
         }];
     };
 }