Click the small Apple icon on the top left of the menu bar.
A menu pops down. Click System Preferences.
System Preferences are displayed. Click Spotlight.
Spotlight Search Results settings are displayed. Scroll down till you see Bookmarks & History.
As you can see Bookmarks & History is checked. Click it once to uncheck it.
Close the window, restart the computer and once you go back to the activity monitor, you will see that the Spotlight Web Content process is not created anymore and the Mac's battery life would receive a marginal improvement.