Chrome on Android has java and c/c++ code. Each “side” have its own set of tools for debugging. Here's some tips.
You can launch the app by using one of the wrappers.
out/Default/bin/content_shell_apk launch [--args='--foo --bar'] 'data:text/html;utf-8,<html>Hello World!</html>' out/Default/bin/chrome_public_apk launch [--args='--foo --bar'] 'data:text/html;utf-8,<html>Hello World!</html>'
Chromium logging from LOG(INFO) etc., is directed to the Android logcat logging facility. You can filter the messages, e.g. view chromium verbose logging, everything else at warning level with:
adb logcat chromium:V cr.SomeComponent:V *:W # or: out/Default/bin/chrome_public_apk logcat
Do not use fprintf or printf debugging! This does not redirect to logcat.
Redirecting stdio to logcat, as documented here, has a bad side-effect that it breaks adb_install.py. See here for details.
While your phone is plugged into USB, use the screenshot.py tool in build/android. envsetup.sh should have put it in your path.
build/android/screenshot.py /tmp/screenshot.png
You can use either hierarchy viewer or monitor to see the Android view hierarchy and see the layout and drawing properties associated with it.
While your phone is plugged into USB, you can inspect the Android view hierarchy using the following command:
ANDROID_HVPROTO=ddm monitor
Setting ANDROID_HVPROTO allows you to inspect debuggable apps on non-rooted devices. When building a local version of Chromium, the build tools automatically add android:debuggable=true to the AndroidManifest.xml, which will allow you to inspect them on rooted devices.
Want to add some additional information to your Views? You can do that by adding the @ViewDebug.ExportedProperty annotation.
Example:
@ViewDebug.ExportedProperty(category="chrome") private int mSuperNiftyDrawingProperty;
For both apk and test targets, pass --wait-for-java-debugger to the wrapper scripts.
Examples:
# Install, launch, and wait: out/Default/bin/chrome_public_apk run --wait-for-java-debugger # Launch, and have GPU process wait rather than Browser process: out/Default/bin/chrome_public_apk launch --wait-for-java-debugger --debug-process-name privileged_process0 # Have Renderers wait: out/Default/bin/chrome_public_apk launch --args="--renderer-wait-for-java-debugger" # Have tests wait: out/Default/bin/run_chrome_public_test_apk --wait-for-java-debugger out/Default/bin/run_chrome_junit_tests --wait-for-java-debugger # Specify custom port via --debug-socket=9999
In Eclipse, make a debug configuration of type “Remote Java Application”. Choose a “Name” and set “Port” to 8700.
Make sure Eclipse Preferences > Run/Debug > Launching > “Build (if required) before launching” is unchecked.
Run Android Device Monitor:
third_party/android_tools/sdk/tools/monitor
Now select the process you want to debug in Device Monitor (the port column should now mention 8700 or xxxx/8700).
Run your debug configuration, and switch to the Debug perspective.
Use the wrapper script gdb command to enter into a gdb shell.
# Attaches to browser process. out/Default/bin/content_shell_apk gdb out/Default/bin/chrome_public_apk gdb # Attaches to gpu process. out/Default/bin/chrome_public_apk gdb --debug-process-name privileged_process0 # Attach to other processes ("chrome_public_apk ps" to show pids). out/Default/bin/chrome_public_apk gdb --pid $PID
Set the target command line flag with --wait-for-debugger.
Launch the debugger using one of the scripts from above.
Type info threads and look for a line like:
11 Thread 2564 clock_gettime () at bionic/libc/arch-arm/syscalls/clock_gettime.S:11
or perhaps:
1 Thread 10870 0x40127050 in nanosleep () from /tmp/user-adb-gdb-libs/system/lib/libc.so
We need to jump out of its sleep routine:
(gdb) thread 11 (gdb) up (gdb) up (gdb) return Make base::debug::BreakDebugger() return now? (y or n) y (gdb) continue
If a crash has generated a tombstone in your device, use:
build/android/tombstones.py --output-directory out/Default
If you have a stack trace (from adb logcat) that needs to be symbolized, copy it into a text file and symbolize with the following command (run from ${CHROME_SRC}):
third_party/android_platform/development/scripts/stack --output-directory out/Default [tombstone file | dump file]
stack can also take its input from stdin:
adb logcat -d | third_party/android_platform/development/scripts/stack --output-directory out/Default
Example:
third_party/android_platform/development/scripts/stack --output-directory out/Default ~/crashlogs/tombstone_07-build231.txt
You will need the ProGuard mapping file that was generated when the application that crashed was built. When building locally, these are found in:
out/Default/apks/ChromePublic.apk.mapping out/Default/apks/ChromeModernPublic.apk.mapping etc.
Build the java_deobfuscate tool:
ninja -C out/Default java_deobfuscate
Then run it via:
# For a file: out/Default/bin/java_deobfuscate PROGUARD_MAPPING_FILE.mapping < FILE # For logcat: adb logcat | out/Default/bin/java_deobfuscate PROGUARD_MAPPING_FILE.mapping
In your build environment:
adb root adb shell stop adb shell setprop log.redirect-stdio true adb shell start
In the source itself, use fprintf(stderr, "message"); whenever you need to output a message.
To run unit tests use the following command:
out/Debug/bin/run_test_name -f <test_filter_if_any> --wait-for-debugger -t 6000
That command will cause the test process to wait until a debugger is attached.
To attach a debugger:
build/android/adb_gdb --output-directory=out/Default --package-name=org.chromium.native_test
After attaching gdb to the process you can use it normally. For example:
(gdb) break main Breakpoint 1 at 0x9750793c: main. (2 locations) (gdb) continue