Add support for TraceEvent before the native library is loaded.

chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellActivity.java

Index: chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellActivity.java
diff --git a/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellActivity.java b/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellActivity.java
index d1fd4eef3b6e1beb4cd3adc59537f4f30dfb9845..abe87f7b87c657b348a5674e3a5d66521241bb4e 100644
--- a/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellActivity.java
+++ b/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellActivity.java
@@ -25,6 +25,7 @@ import org.chromium.base.BaseSwitches;
 import org.chromium.base.CommandLine;
 import org.chromium.base.ContentUriUtils;
 import org.chromium.base.MemoryPressureListener;
+import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.base.library_loader.LibraryProcessType;
@@ -121,9 +122,15 @@ public class ChromeShellActivity extends ActionBarActivity implements AppMenuPro
     @Override
     @SuppressFBWarnings("DM_EXIT")
     protected void onCreate(final Bundle savedInstanceState) {
+        // Enable tracing as early as possible if required
+        ContentApplication.initCommandLine(this);
+        if (CommandLine.getInstance().hasSwitch("trace-startup")) {
+            TraceEvent.enableEarlyTracing();
+        }
+        TraceEvent.begin("ChromeShellActivity.onCreate");
+
         super.onCreate(savedInstanceState);
 
-        ContentApplication.initCommandLine(this);
         waitForDebuggerIfNeeded();
 
         DeviceUtils.addDeviceSpecificUserAgentSwitch(this);
@@ -150,6 +157,8 @@ public class ChromeShellActivity extends ActionBarActivity implements AppMenuPro
         } catch (ProcessInitException e) {
             Log.e(TAG, "Unable to load native library.", e);
             System.exit(-1);
+        } finally {
+            TraceEvent.end("ChromeShellActivity.onCreate");
         }
     }