Include IME trace in Winscope

This CL makes the necessary additions for Winscope to:
   1) Accept an IME trace output file (ime_trace.pb) and display its contents
   2) Start IME trace from the web interface and display the contents along with other traces

Bug: 154348613
Test: build and run the code using "yarn run dev"
      build and flash the android code to a device
      start and stop IME trace from the command line and then upload the file into Winscope or
      start IME trace from the web interface, open an IME on the android device to generate logs, end trace from the web interface to see the logs
Change-Id: I090c9e3ca4e334a273269d11db006ec8cb63756c

tools/winscope/adb_proxy/winscope_proxy.py

@@ -47,7 +47,7 @@ LOG_LEVEL = logging.WARNING
 PORT = 5544
 
 # Keep in sync with WINSCOPE_PROXY_VERSION in Winscope DataAdb.vue
-VERSION = '0.6'
+VERSION = '0.7'
 
 WINSCOPE_VERSION_HEADER = "Winscope-Proxy-Version"
 WINSCOPE_TOKEN_HEADER = "Winscope-Token"
@@ -139,6 +139,11 @@ TRACE_TARGETS = {
         'su root cmd window logging start\necho "WM logging started."',
         'su root cmd window logging stop >/dev/null 2>&1'
     ),
+    "ime_trace": TraceTarget(
+        File("/data/misc/wmtrace/ime_trace.pb", "ime_trace"),
+        'su root ime tracing start\necho "IME trace started."',
+        'su root ime tracing stop >/dev/null 2>&1'
+    ),
 }