ELECTRON-655: implement dynamic chrome command line flags logic (#471)

- implement dynamic chrome command line flags logic
- added more validation

js/main.js

@@ -135,9 +135,6 @@ function setChromeFlags() {
             app.commandLine.appendSwitch('auth-negotiate-delegate-whitelist', config.customFlags.authNegotiateDelegateWhitelist);
         }
 
-        // ELECTRON-261: Windows 10 Screensharing issues. We set chrome flags
-        // to disable gpu which fixes the black screen issue observed on
-        // multiple monitors
         if (config.customFlags.disableGpu) {
             log.send(logLevels.INFO, 'Setting disable gpu, gpu compositing and d3d11 flags to true');
             app.commandLine.appendSwitch("disable-gpu", true);
@@ -148,6 +145,53 @@ function setChromeFlags() {
     }
 
     app.commandLine.appendSwitch("disable-background-timer-throttling", true);
+
+    if (isDevEnv) {
+        setChromeFlagsFromCommandLine();
+    }
+
+}
+
+function setChromeFlagsFromCommandLine() {
+
+    log.send(logLevels.INFO, 'Setting chrome flags from command line arguments!');
+
+    let chromeFlagsFromCmd = getCmdLineArg(process.argv, '--chrome-flags=', false);
+    if (!chromeFlagsFromCmd) {
+        return;
+    }
+
+    let chromeFlagsArgs = chromeFlagsFromCmd.substr(15);
+    if (!chromeFlagsArgs) {
+        return;
+    }
+
+    let flags = chromeFlagsArgs.split(',');
+    if (!flags || !Array.isArray(flags)) {
+        return;
+    }
+
+    for (let key in flags) {
+
+        if (!Object.prototype.hasOwnProperty.call(flags, key)) {
+            continue;
+        }
+
+        if (!flags[key]) {
+            return;
+        }
+
+        let flagArray = flags[key].split(':');
+
+        if (flagArray && Array.isArray(flagArray) && flagArray.length > 0) {
+            let chromeFlagKey = flagArray[0];
+            let chromeFlagValue = flagArray[1];
+            log.send(logLevels.INFO, `Setting chrome flag ${chromeFlagKey} to ${chromeFlagValue}`);
+            app.commandLine.appendSwitch(chromeFlagKey, chromeFlagValue);
+        }
+
+    }
+
 }
 
 // Set the chrome flags