Log WebRTC version.

Signal.xcodeproj/project.pbxproj

@@ -2599,6 +2599,7 @@
 				451DE9EE1DC1546A00810E42 /* [Carthage] Copy Frameworks */,
 				453518771FC635DD00210559 /* Embed App Extensions */,
 				4535189F1FC63DBF00210559 /* Embed Frameworks */,
+				34C239432180B01B00B6108F /* ShellScript */,
 			);
 			buildRules = (
 			);
@@ -2921,6 +2922,19 @@
 			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
 			showEnvVarsInLog = 0;
 		};
+		34C239432180B01B00B6108F /* ShellScript */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+			);
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "# Capture hash & comment from last WebRTC git commit.\ncd $PROJECT_DIR/ThirdParty/WebRTC/\n_git_commit=`git log --pretty=oneline | head -1`\ncd $PROJECT_DIR\n# Remove existing .plist entry, if any.\n/usr/libexec/PlistBuddy -c \"Delete WebRTCCommit\" Signal/Signal-Info.plist || true\n# Add new .plist entry.\n/usr/libexec/PlistBuddy -c \"add WebRTCCommit string '$_git_commit'\" Signal/Signal-Info.plist\n";
+		};
 		451DE9EE1DC1546A00810E42 /* [Carthage] Copy Frameworks */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;

Signal/Signal-Info.plist

@@ -135,5 +135,7 @@
 	</array>
 	<key>UIViewControllerBasedStatusBarAppearance</key>
 	<true/>
+	<key>WebRTCCommit</key>
+	<string>af8b6b232df749574744cd5d092227f8559969f9 M69</string>
 </dict>
 </plist>

Signal/src/AppDelegate.m

@@ -476,6 +476,7 @@ static NSTimeInterval launchStartedAt;
     free(machine);
 
     OWSLogInfo(@"iPhone Version: %@", platform);
+    OWSLogInfo(@"WebRTC Commit: %@", [[NSBundle mainBundle] objectForInfoDictionaryKey:@"WebRTCCommit"]);
 }
 
 - (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken