clean up some .gitignores

I'd be tempted to remove even another half of these,
but I'm not really clear on what they are.

Change-Id: Ib18f02d651f32d4437f55e79c2d05b5e34b0b1e1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/213844
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
diff --git a/.gitignore b/.gitignore
index 2bdf59f..e909ea7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,9 +3,7 @@
 *.iml
 .DS_Store
 .android_config
-.deps_sha1
 .gclient*
-.gm-actuals
 .gradle
 .idea
 .cproject
@@ -14,7 +12,6 @@
 .settings/
 TAGS
 bower_components
-common
 imgui.ini
 infra/bots/README.recipes.md
 infra/bots/gen_tasks_aux.go
@@ -32,25 +29,19 @@
 platform_tools/android/apps/*.hprof
 platform_tools/android/apps/*/.externalNativeBuild
 
-sampleapp_prefs.txt
 /skps
 /svgs
-third_party/externals
 tools/skp/page_sets/data/*.json
 tools/skp/page_sets/data/*.wpr
-xcodebuild
 
-/build
+common
 buildtools
-third_party/llvm-build
+third_party/externals
+
 bin/gn
 bin/gn.exe
 bin/clang-format
 bin/clang-format.exe
-bin/clang_win
-
-vulkan-out
-gl-out
 
 node_modules
 tools/lottiecap/filmstrip.png