Cleanup perfetto_cmd.cc

- Move android-specific stuff to perfetto_cmd_android.cc
- Move dropbox code into android_internal
- Get rid of AndroidTaskRunner. Looks like it's not necessary
  anymore.
- Get rid of libandroid.so dependency (previously required for
  AndroidTaskRunner). This is a huge improvement because
  libandroid.so was used to pull transitively hundreds of .so(s)

Test: manual
Change-Id: I2d9a78a6a9cd146c3693fbccd88467acfbb2eac5
diff --git a/src/android_internal/BUILD.gn b/src/android_internal/BUILD.gn
index 52e86e1..d1bea0f 100644
--- a/src/android_internal/BUILD.gn
+++ b/src/android_internal/BUILD.gn
@@ -20,6 +20,7 @@
   ]
   sources = [
     "atrace_hal.h",
+    "dropbox_service.h",
     "health_hal.h",
     "incident_service.h",
     "power_stats_hal.h",
@@ -52,6 +53,7 @@
   if (perfetto_build_with_android) {
     sources = [
       "atrace_hal.cc",
+      "dropbox_service.cc",
       "health_hal.cc",
       "incident_service.cc",
       "power_stats_hal.cc",
@@ -65,6 +67,7 @@
       "log",
       "hidlbase",
       "incident",
+      "services",
       "utils",
     ]
   }