Splits components/sessions into separate core and content targets.

components/sessions/BUILD.gn

Index: components/sessions/BUILD.gn
diff --git a/components/sessions/BUILD.gn b/components/sessions/BUILD.gn
index f2ada0545aee1890d319f722324ae5c0f51b0e5d..1b75012a6867470cb07afa3403e8132056193e8c 100644
--- a/components/sessions/BUILD.gn
+++ b/components/sessions/BUILD.gn
@@ -6,14 +6,12 @@ if (is_android) {
   import("//build/config/android/config.gni")
 }
 
-component("sessions") {
+# TODO(rohitrao): sessions_core is defined as a source_set because it declares a
+# static function that it does not define.  This prevents it from linking as a
+# shared_library.  It also cannot be a static_library because it will be linked
+# into multiple shared libraries.  Revisit this setup if necessary.
+source_set("sessions_core") {
   sources = [
-    # TODO(rohitrao): Split this target into three separate core, content,
-    # and web targets.
-    "content/content_serialized_navigation_builder.cc",
-    "content/content_serialized_navigation_builder.h",
-    "content/content_serialized_navigation_driver.cc",
-    "content/content_serialized_navigation_driver.h",
     "core/serialized_navigation_driver.h",
     "serialized_navigation_entry.cc",
     "serialized_navigation_entry.h",
@@ -25,8 +23,6 @@ component("sessions") {
 
   deps = [
     "//base",
-    "//base/third_party/dynamic_annotations",
-    "//content/public/browser",
     "//skia",
     "//ui/base",
     "//url",
@@ -37,6 +33,26 @@ component("sessions") {
   }
 }
 
+component("sessions_content") {
+  sources = [
+    "content/content_serialized_navigation_builder.cc",
+    "content/content_serialized_navigation_builder.h",
+    "content/content_serialized_navigation_driver.cc",
+    "content/content_serialized_navigation_driver.h",
+  ]
+
+  defines = [ "SESSIONS_IMPLEMENTATION" ]
+
+  deps = [
+    ":sessions_core",
+    "//base",
+    "//base/third_party/dynamic_annotations",
+    "//content/public/browser",
+    "//ui/base",
+    "//url",
+  ]
+}
+
 static_library("test_support") {
   testonly = true
   sources = [