Add a flag to let render process wait for java debugger

A switch RENDERER_WAIT_FOR_JAVA_DEBUGGER is newly added to block
ChildProcessMain thread of ChildProcessService until a Java debugger is
attached.

BUG=378975

Review URL: https://codereview.chromium.org/511683003

Cr-Commit-Position: refs/heads/master@{#292733}

base/android/java/src/org/chromium/base/BaseSwitches.java

@@ -12,6 +12,9 @@ public abstract class BaseSwitches {
     // Block onCreate() of Chrome until a Java debugger is attached.
     public static final String WAIT_FOR_JAVA_DEBUGGER = "wait-for-java-debugger";
 
+    // Block ChildProcessMain thread of render process service until a Java debugger is attached.
+    public static final String RENDERER_WAIT_FOR_JAVA_DEBUGGER = "renderer-wait-for-java-debugger";
+
     // Force low-end device when set to 1;
     // Force non-low-end device when set to 0;
     // Auto-detect low-end device when set to other values or empty;

content/browser/renderer_host/render_process_host_impl.cc

@@ -1248,6 +1248,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kMediaDrmEnableNonCompositing,
     switches::kNetworkCountryIso,
     switches::kDisableWebAudio,
+    switches::kRendererWaitForJavaDebugger,
 #endif
 #if defined(OS_MACOSX)
     // Allow this to be set when invoking the browser and relayed along.

content/public/android/java/src/org/chromium/content/app/ChildProcessService.java

@@ -16,6 +16,7 @@ import android.os.RemoteException;
 import android.util.Log;
 import android.view.Surface;
 
+import org.chromium.base.BaseSwitches;
 import org.chromium.base.CalledByNative;
 import org.chromium.base.CommandLine;
 import org.chromium.base.JNINamespace;
@@ -154,6 +155,11 @@ public class ChildProcessService extends Service {
                         }
                     }
                     CommandLine.init(mCommandLineParams);
+                    if (CommandLine.getInstance().hasSwitch(
+                            BaseSwitches.RENDERER_WAIT_FOR_JAVA_DEBUGGER)) {
+                        android.os.Debug.waitForDebugger();
+                    }
+
                     try {
                         LibraryLoader.loadNow(getApplicationContext(), false);
                         isLoaded = true;

content/public/common/content_switches.cc

@@ -889,6 +889,10 @@ const char kNetworkCountryIso[] = "network-country-iso";
 
 // Enables remote debug over HTTP on the specified socket name.
 const char kRemoteDebuggingSocketName[]     = "remote-debugging-socket-name";
+
+// Block ChildProcessMain thread of the renderer's ChildProcessService until a
+// Java debugger is attached.
+const char kRendererWaitForJavaDebugger[] = "renderer-wait-for-java-debugger";
 #endif
 
 // Disable web audio API.

content/public/common/content_switches.h

@@ -256,6 +256,7 @@ CONTENT_EXPORT extern const char kForceUseOverlayEmbeddedVideo[];
 CONTENT_EXPORT extern const char kHideScrollbars[];
 extern const char kNetworkCountryIso[];
 CONTENT_EXPORT extern const char kRemoteDebuggingSocketName[];
+CONTENT_EXPORT extern const char kRendererWaitForJavaDebugger[];
 #endif
 
 CONTENT_EXPORT extern const char kDisableWebAudio[];