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 9db47f5bcdd9c3f4371c5351d3ccbcdfffedc7c8..5aad42a988f62ae6f050b0bb1fa1e20f6aded93f 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
@@ -23,6 +23,7 @@ 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.ProcessInitException;
@@ -116,9 +117,15 @@ 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")) {

[pasko, 2015/01/27 15:36:02]

FYI: we are going to have global tracing state in the system, so this piece
would check for a special file on the device

[Benoit L, 2015/02/09 16:34:01]

Acknowledged.

+            TraceEvent.enableEarlyTracing();
+        }
+        TraceEvent.begin("ChromeShellActivity.onCreate");
+
         super.onCreate(savedInstanceState);
 
-        ContentApplication.initCommandLine(this);
         waitForDebuggerIfNeeded();
 
         DeviceUtils.addDeviceSpecificUserAgentSwitch(this);
@@ -144,6 +151,8 @@ 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");
         }
     }