Using crashpad with content shell

When running web tests, it is possible to use crashpad/breakpad to capture stack traces on crashes while running without a debugger attached and with the sandbox enabled.

Setup

On all platforms, build the target blink_tests.

Mac: Add enable_dsyms = 1 to your gn build arguments before building. This slows down linking several minutes, so don't just always set it by default.

Then, create a directory where the crash dumps will be stored:

Linux/Mac:
```
mkdir /tmp/crashes
```

Android:

adb root
adb shell mkdir /data/data/org.chromium.content_shell_apk/cache

Windows:
```
mkdir %TEMP%\crashes
```

Running content shell with crashpad

Crashpad can be enabled by passing --enable-crash-reporter and --crash-dumps-dir to content shell:

Linux:

out/Debug/content_shell --enable-crash-reporter \
    --crash-dumps-dir=/tmp/crashes chrome://crash

Mac:

out/Debug/Content\ Shell.app/Contents/MacOS/Content\ Shell \
    --enable-crash-reporter --crash-dumps-dir=/tmp/crashes chrome://crash

Windows:

out\Default\content_shell.exe --enable-crash-reporter ^
    --crash-dumps-dir=%TEMP%\crashes chrome://crash

Android:

out/Default/bin/content_shell_apk install
out/Default/bin/content_shell_apk launch chrome://crash
--args="--enable-crash-reporter --crash-dumps-dir=/data/data/org.chromium.content_shell_apk/cache"

Retrieving the crash dump

On Android, we first have to retrieve the crash dump. On other platforms, this step can be skipped.

Android:

adb pull $(adb shell ls /data/data/org.chromium.content_shell_apk/cache/pending/*.dmp) /tmp/chromium-renderer-minidump.dmp

Symbolizing the crash dump

On all platforms except for Windows, we need to convert the debug symbols to a format that breakpad can understand.

Linux:

components/crash/content/tools/generate_breakpad_symbols.py \
    --build-dir=out/Default --binary=out/Default/content_shell \
    --symbols-dir=out/Default/content_shell.breakpad.syms --clear --jobs=16

Mac:

components/crash/content/tools/generate_breakpad_symbols.py \
    --build-dir=out/Default \
    --binary=out/Default/Content\ Shell.app/Contents/MacOS/Content\ Shell \
    --symbols-dir=out/Default/content_shell.breakpad.syms --clear --jobs=16

Android:

components/crash/content/tools/generate_breakpad_symbols.py \
    --build-dir=out/Default \
    --binary=out/Default/lib/libcontent_shell_content_view.so \
    --symbols-dir=out/Default/content_shell.breakpad.syms --clear \
    --platform=android

Now we can generate a stack trace from the crash dump. Assuming the crash dump is in minidump.dmp:

Linux/Android/Mac:

out/Default/minidump_stackwalk minidump.dmp out/Debug/content_shell.breakpad.syms

Windows:

"c:\Program Files (x86)\Windows Kits\8.0\Debuggers\x64\cdb.exe" ^
    -y out\Default -c ".ecxr;k30;q" -z minidump.dmp