Tab Search: Add .gitignore file

Bug: 1099917
Change-Id: I95480e8bef7de7197642997cebf1296b5c0a1563
Reviewed-on: https://chrome-internal-review.googlesource.com/c/chrome/browser/resources/tab_search/+/3187724Reviewed-by: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819571}

chrome/browser/resources/tab_search_merge/.gitignore

+*.bak
+*.mk
+*.ncb
+*.opensdf
+*.orig
+*.pdb
+*.props
+*.pyc
+*.pyproj
+*.rules
+*.sdf
+*.sln
+*.sublime-project
+*.sublime-workspace
+*.suo
+*.targets
+*.user
+*.vc.opendb
+*.vcproj
+*.vcxproj
+*.vcxproj.filters
+*.vpj
+*.vpw
+*.vpwhistu
+*.vtg
+*.xcodeproj
+*.xcworkspace
+*.VC.db
+*_proto.xml
+*_proto_cpp.xml
+*~
+!Android.mk
+.*.sw?
+.DS_Store
+.android
+.ccls-cache
+.cipd
+.classpath
+.code-coverage
+.cproject
+.emulator_sdk
+.gdb_history
+.gdbinit
+.landmines
+.metadata
+.project
+.pydevproject
+.checkstyle
+*.class
+compile_commands.json
+cscope.*
+GPATH
+GRTAGS
+GSYMS
+GTAGS
+Session.vim
+tags
+Thumbs.db
+v8.log
+vs-chromium-project.txt
+/.cache/
+/.clangd/
+/.clangd-index/
+# Settings directories for eclipse
+/.externalToolBuilders/
+/.settings/
+/.vs/
+# Visual Studio Code
+.vscode/
+/_out
+/android_emulator_sdk
+/ash/ash_unittests_run.xml
+/base/base_unittests_run.xml
+/.cache/
+# Ignore IntelliJ files.
+.idea/
+# Ignore cache folder created by clangd
+.cache