so that users does not have to specify command line arguments.

It generates logs:

V/chromium(22041): [VERBOSE1:blimp_message_pump.cc(59)] Received <BlimpMessage type=COMPOSITOR target_tab_id=0 byte_size=61379>
V/chromium(22041): [VERBOSE1:blimp_connection.cc(66)] Sending <BlimpMessage type=PROTOCOL_CONTROL subtype=CHECKPOINT_ACK checkpoint_id=20 byte_size=15>

BUG=596796

Review URL: https://codereview.chromium.org/1841183002

Cr-Commit-Position: refs/heads/master@{#383840}

blimp/client/app/blimp_startup.cc

@@ -4,6 +4,7 @@
 
 #include "blimp/client/app/blimp_startup.h"
 
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ -33,6 +34,13 @@ namespace blimp {
 namespace client {
 
 void InitializeLogging() {
+  // TODO(haibinlu): Remove this before release.
+  // Enables a few verbose log by default.
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch("vmodule")) {
+    base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+        "vmodule", "blimp_message_pump=1, blimp_connection=1");
+  }
+
   logging::LoggingSettings settings;
 #if defined(OS_ANDROID)
   settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;

blimp/net/blimp_connection.cc

@@ -63,7 +63,7 @@ void BlimpMessageSender::ProcessMessage(
     scoped_ptr<BlimpMessage> message,
     const net::CompletionCallback& callback) {
   DCHECK(error_observer_);
-  DVLOG(2) << "Sender::ProcessMessage " << *message;
+  VLOG(1) << "Sending " << *message;
 
   if (message->ByteSize() > static_cast<int>(kMaxPacketPayloadSizeBytes)) {
     DLOG(ERROR) << "Message rejected (too large): " << *message;

blimp/net/blimp_message_pump.cc

@@ -56,7 +56,7 @@ void BlimpMessagePump::OnReadPacketComplete(int result) {
   if (result >= 0) {
     scoped_ptr<BlimpMessage> message(new BlimpMessage);
     if (message->ParseFromArray(buffer_->data(), result)) {
-      DVLOG(2) << "OnReadPacketComplete, result=" << *message;
+      VLOG(1) << "Received " << *message;
       processor_->ProcessMessage(
           std::move(message),
           base::Bind(&BlimpMessagePump::OnProcessMessageComplete,