Replace HistoryQuickProvider protobuf-based caching with an SQLite-based database.

tools/valgrind/memcheck/suppressions.txt

 # There are four kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 5759 matching lines @@
    ...
    fun:_ZNK7SkPaint14descriptorProcEPK8SkMatrixPFvPK12SkDescriptorPvES6_b
 }
 {
    bug_140628
    Memcheck:Leak
    ...
    fun:_ZN15ExtensionAction16RunIconAnimationEi
    fun:_ZN15ExtensionAction13SetAppearanceEiNS_10AppearanceE
 }
+{
+   bug_144081
+   Memcheck:Leak
+   ...
+   fun:_ZN7history19URLIndexPrivateData18RebuildFromHistoryEPNS_15HistoryDatabaseE13scoped_refptrIS0_E
+   fun:_ZN7history16InMemoryURLIndex35RebuildPrivateDataFromHistoryDBTask13RunOnDBThreadEPNS_14HistoryBackendEPNS_15HistoryDatabaseE
+}
+{
+   bug_144082
+   Memcheck:Leak
+   ...
+   fun:_ZN7history16InMemoryURLIndex37DoneRebuidingPrivateDataFromHistoryDBEb13scoped_refptrINS_19URLIndexPrivateDataEE
+   fun:_ZN7history16InMemoryURLIndex35RebuildPrivateDataFromHistoryDBTask19DoneRunOnMainThreadEv
+}
+{
+   bug_144083
+   Memcheck:Leak
+   ...
+   fun:_ZN7history25InitializeSchemeWhitelistEPSt3setISsSt4lessISsESaISsEE
+   fun:_ZN7history19URLIndexPrivateDataC1ERK8FilePathRKSs
+   fun:_ZN7history16InMemoryURLIndexC1EP7ProfileRK8FilePathRKSs
+   fun:_ZN14HistoryService4InitERK8FilePathP15BookmarkServicebb
+   fun:_ZN14TestingProfile18InitHistoryServiceEP14HistoryServiceb
+}
 
 #-----------------------------------------------------------------------
 # 4. These only occur on our Google workstations
 
 {
    bug_todo_getdelim
    Memcheck:Leak
    fun:malloc
    fun:getdelim
    ...
    fun:call_init
    fun:_dl_init
 }
 {
    bug_todo_getdelim2
    Memcheck:Leak
    fun:malloc
    fun:getdelim
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
 }
 {
    bug_todo_grep
    Memcheck:Leak
    fun:malloc
    obj:/bin/grep
    obj:/bin/grep
 }