fix deps for target renderer.lib

Building renderer.lib clean directly fails.

Repro steps:
1. rmdir /s/q out\default
2. gn gen out\default
3. autoninja.bat -C out\default obj/chrome/renderer/renderer.lib

For details on the process to find these see the comments in crrev.com/c/2153933

Change-Id: Ia4b708b7e9a8bf50294f68437fcb9a38eaf4b595
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2153935
Commit-Queue: Brian Manthos <brianman@microsoft.com>
Reviewed-by: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760279}

chrome/renderer/BUILD.gn

@@ -126,6 +126,8 @@ jumbo_static_library("renderer") {
 
   defines = []
 
+  public_deps = [ "//components/contextual_search:buildflags" ]
+
   deps = [
     "//chrome:resources",
     "//chrome:strings",
@@ -343,7 +345,7 @@ jumbo_static_library("renderer") {
       "//media/cast:sender",
       "//services/network/public/cpp",
     ]
-    public_deps = [ "//ipc" ]
+    public_deps += [ "//ipc" ]
   }
   if (enable_extensions) {
     sources += [